hash_map (STL/CLR)

The template class describes an object that controls a varying-length sequence of elements that has bidirectional access. You use the container hash_map to manage a sequence of elements as a hash table, each table entry storing a bidirectional linked list of nodes, and each node storing one element. An element consists of a key, for ordering the sequence, and a mapped value, which goes along for the ride.

In the description below, GValue is the same as:

Microsoft::VisualC::StlClr::GenericPair<GKey, GMapped>

where:

GKey is the same as Key unless the latter is a ref type, in which case it's Key^

GMapped is the same as Mapped unless the latter is a ref type, in which case it's Mapped^

Syntax

template<typename Key,
    typename Mapped>
    ref class hash_map
        :   public
        System::ICloneable,
        System::Collections::IEnumerable,
        System::Collections::ICollection,
        System::Collections::Generic::IEnumerable<GValue>,
        System::Collections::Generic::ICollection<GValue>,
        System::Collections::Generic::IList<GValue>,
        System::Collections::Generic::IDictionary<Gkey, GMapped>,
        Microsoft::VisualC::StlClr::IHash<Gkey, GValue>
    { ..... };

Parameters

Key
The type of the key component of an element in the controlled sequence.

Mapped
The type of the other component of an element in the controlled sequence.

Requirements

Header: <cliext/hash_map>

Namespace: cliext

Declarations

Type definition	Description
hash_map::const_iterator	The type of a constant iterator for the controlled sequence.
hash_map::const_reference	The type of a constant reference to an element.
hash_map::const_reverse_iterator	The type of a constant reverse iterator for the controlled sequence.
hash_map::difference_type	The type of a (possibly signed) distance between two elements.
hash_map::generic_container	The type of the generic interface for the container.
hash_map::generic_iterator	The type of an iterator for the generic interface for the container.
hash_map::generic_reverse_iterator	The type of a reverse iterator for the generic interface for the container.
hash_map::generic_value	The type of an element for the generic interface for the container.
hash_map::hasher	The hashing delegate for a key.
hash_map::iterator	The type of an iterator for the controlled sequence.
hash_map::key_compare	The ordering delegate for two keys.
hash_map::key_type	The type of an ordering key.
hash_map::mapped_type	The type of the mapped value associated with each key.
hash_map::reference	The type of a reference to an element.
hash_map::reverse_iterator	The type of a reverse iterator for the controlled sequence.
hash_map::size_type	The type of a (non-negative) distance between two elements.
hash_map::value_compare	The ordering delegate for two element values.
hash_map::value_type	The type of an element.

Member function	Description
hash_map::begin	Designates the beginning of the controlled sequence.
hash_map::bucket_count	Counts the number of buckets.
hash_map::clear	Removes all elements.
hash_map::count	Counts elements matching a specified key.
hash_map::empty	Tests whether no elements are present.
hash_map::end	Designates the end of the controlled sequence.
hash_map::equal_range	Finds range that matches a specified key.
hash_map::erase	Removes elements at specified positions.
hash_map::find	Finds an element that matches a specified key.
hash_map::hash_delegate	Copies the hashing delegate for a key.
hash_map::hash_map	Constructs a container object.
hash_map::insert	Adds elements.
hash_map::key_comp	Copies the ordering delegate for two keys.
hash_map::load_factor	Counts the average elements per bucket.
hash_map::lower_bound	Finds beginning of range that matches a specified key.
hash_map::make_value	Constructs a value object.
hash_map::max_load_factor	Gets or sets the maximum elements per bucket.
hash_map::rbegin	Designates the beginning of the reversed controlled sequence.
hash_map::rehash	Rebuilds the hash table.
hash_map::rend	Designates the end of the reversed controlled sequence.
hash_map::size	Counts the number of elements.
hash_map::swap	Swaps the contents of two containers.
hash_map::to_array	Copies the controlled sequence to a new array.
hash_map::upper_bound	Finds end of range that matches a specified key.
hash_map::value_comp	Copies the ordering delegate for two element values.

Operator	Description
hash_map::operator=	Replaces the controlled sequence.
hash_map::operator[]	Maps a key to its associated mapped value.

Interfaces

Interface	Description
ICloneable	Duplicate an object.
IEnumerable	Sequence through elements.
ICollection	Maintain group of elements.
IEnumerable<T>	Sequence through typed elements.
ICollection<T>	Maintain group of typed elements.
IDictionary<TKey,TValue>	Maintain group of {key, value} pairs.
IHash<Key, Value>	Maintain generic container.

Remarks

The object allocates and frees storage for the sequence it controls as individual nodes in a bidirectional linked list. To speed access, the object also maintains a varying-length array of pointers into the list (the hash table), effectively managing the whole list as a sequence of sublists, or buckets. It inserts elements into a bucket that it keeps ordered by altering the links between nodes, never by copying the contents of one node to another. That means you can insert and remove elements freely without disturbing remaining elements.

The object orders each bucket it controls by calling a stored delegate object of type hash_set::key_compare. You can specify the stored delegate object when you construct the hash_set; if you specify no delegate object, the default is the comparison operator<=(key_type, key_type).

You access the stored delegate object by calling the member function hash_set::key_comp(). Such a delegate object must define equivalent ordering between keys of type hash_set::key_type. That means, for any two keys X and Y:

key_comp()(X, Y) returns the same Boolean result on every call.

If key_comp()(X, Y) && key_comp()(Y, X) is true, then X and Y are said to have equivalent ordering.

Any ordering rule that behaves like operator<=(key_type, key_type), operator>=(key_type, key_type) or operator==(key_type, key_type) defines equivalent ordering.

The container ensures only that elements whose keys have equivalent ordering (and which hash to the same integer value) are adjacent within a bucket. Unlike template class hash_multimap, an object of template class hash_map ensures that keys for all elements are unique. (No two keys have equivalent ordering.)

The object determines which bucket should contain a given ordering key by calling a stored delegate object of type hash_set::hasher. You access this stored object by calling the member function hash_set::hash_delegate to obtain an integer value that depends on the key value. You can specify the stored delegate object when you construct the hash_set; if you specify no delegate object, the default is the function System::Object::hash_value(key_type). That means, for any keys X and Y:

hash_delegate()(X) returns the same integer result on every call.

If X and Y have equivalent ordering, then hash_delegate()(X) should return the same integer result as hash_delegate()(Y).

Each element contains a separate key and a mapped value. The sequence is represented in a way that permits lookup, insertion, and removal of an arbitrary element in constant time. That is, the number of operations is independent of the number of elements in the sequence, at least in the best of cases. Moreover, inserting an element invalidates no iterators, and removing an element invalidates only those iterators that point at the removed element.

If hashed values aren't uniformly distributed, however, a hash table can degenerate. In the extreme (for a hash function that always returns the same value), lookup, insertion, and removal are proportional to the number of elements in the sequence (linear time). The container endeavors to choose a reasonable hash function, mean bucket size, and hash-table size (total number of buckets), but you can override any or all of these choices. See, for example, the functions hash_set::max_load_factor and hash_set::rehash.

A hash_map supports bidirectional iterators, which means you can step to adjacent elements given an iterator that designates an element in the controlled sequence. A special head node corresponds to the iterator returned by end(). You can decrement this iterator to reach the last element in the controlled sequence, if present. You can increment a hash_map iterator to reach the head node, and it will then compare equal to end(). But you can't dereference the iterator returned by end().

You can't refer to a hash_map element directly given its numerical position; that requires a random-access iterator.

A hash_map iterator stores a handle to its associated hash_map node, which in turn stores a handle to its associated container. You can use iterators only with their associated container objects. A hash_map iterator remains valid so long as its associated hash_map node is associated with some hash_map. Moreover, a valid iterator is dereferencable. You can use it to access or alter the element value it designates, so long as it's not equal to end().

Erasing or removing an element calls the destructor for its stored value. Destroying the container erases all elements. Thus, a container whose element type is a ref class ensures that no elements outlive the container. Note, however, that a container of handles doesn't* destroy its elements.

Members

hash_map::begin

Designates the beginning of the controlled sequence.

Syntax

iterator begin();

Remarks

The member function returns a bidirectional iterator that designates the first element of the controlled sequence, or just beyond the end of an empty sequence. You use it to obtain an iterator that designates the current beginning of the controlled sequence, but its status can change if the length of the controlled sequence changes.

Example

// cliext_hash_map_begin.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect first two items
    Myhash_map::iterator it = c1.begin();
    System::Console::WriteLine("*begin() = [{0} {1}]",
        it->first, it->second);
    ++it;
    System::Console::WriteLine("*++begin() = [{0} {1}]",
        it->first, it->second);
    return (0);
    }

[a 1] [b 2] [c 3]
*begin() = [a 1]
*++begin() = [b 2]

hash_map::bucket_count

Counts the number of buckets.

Syntax

int bucket_count();

Remarks

The member function returns the current number of buckets. You use it to determine the size of the hash table.

Example

// cliext_hash_map_bucket_count.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1 = gcnew Myhash_map;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect current parameters
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // change max_load_factor and redisplay
    c1.max_load_factor(0.25f);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // rehash and redisplay
    c1.rehash(100);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    return (0);
    }

[a 1] [b 2] [c 3]
bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 4

bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 0.25

bucket_count() = 128
load_factor() = 0.0234375
max_load_factor() = 0.25

hash_map::clear

Removes all elements.

Syntax

void clear();

Remarks

The member function effectively calls erase(begin(), end()). You use it to ensure that the controlled sequence is empty.

Example

// cliext_hash_map_clear.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // clear the container and reinspect
    c1.clear();
    System::Console::WriteLine("size() = {0}", c1.size());

    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));

    // display contents " [a 1] [b 2]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    c1.clear();
    System::Console::WriteLine("size() = {0}", c1.size());
    return (0);
    }

[a 1] [b 2] [c 3]
size() = 0
[a 1] [b 2]
size() = 0

hash_map::const_iterator

The type of a constant iterator for the controlled sequence.

Syntax

typedef T2 const_iterator;

Remarks

The type describes an object of unspecified type T2 that can serve as a constant bidirectional iterator for the controlled sequence.

Example

// cliext_hash_map_const_iterator.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    Myhash_map::const_iterator cit = c1.begin();
    for (; cit != c1.end(); ++cit)
        System::Console::Write("[{0} {1}] ", cit->first, cit->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]

hash_map::const_reference

The type of a constant reference to an element.

Syntax

typedef value_type% const_reference;

Remarks

The type describes a constant reference to an element.

Example

// cliext_hash_map_const_reference.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    Myhash_map::const_iterator cit = c1.begin();
    for (; cit != c1.end(); ++cit)
        {   // get a const reference to an element
        Myhash_map::const_reference cref = *cit;
        System::Console::Write("[{0} {1}] ", cref->first, cref->second);
        }
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]

hash_map::const_reverse_iterator

The type of a constant reverse iterator for the controlled sequence.

Syntax

typedef T4 const_reverse_iterator;

Remarks

The type describes an object of unspecified type T4 that can serve as a constant reverse iterator for the controlled sequence.

Example

// cliext_hash_map_const_reverse_iterator.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]" reversed
    Myhash_map::const_reverse_iterator crit = c1.rbegin();
    for (; crit != c1.rend(); ++crit)
        System::Console::Write("[{0} {1}] ", crit->first, crit->second);
    System::Console::WriteLine();
    return (0);
    }

[c 3] [b 2] [a 1]

hash_map::count

Finds the number of elements matching a specified key.

Syntax

size_type count(key_type key);

Parameters

key
Key value to search for.

Remarks

The member function returns the number of elements in the controlled sequence that have equivalent ordering with key. You use it to determine the number of elements currently in the controlled sequence that match a specified key.

Example

// cliext_hash_map_count.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    System::Console::WriteLine("count(L'A') = {0}", c1.count(L'A'));
    System::Console::WriteLine("count(L'b') = {0}", c1.count(L'b'));
    System::Console::WriteLine("count(L'C') = {0}", c1.count(L'C'));
    return (0);
    }

[a 1] [b 2] [c 3]
count(L'A') = 0
count(L'b') = 1
count(L'C') = 0

hash_map::difference_type

The types of a signed distance between two elements.

Syntax

typedef int difference_type;

Remarks

The type describes a possibly negative element count.

Example

// cliext_hash_map_difference_type.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // compute positive difference
    Myhash_map::difference_type diff = 0;
    for (Myhash_map::iterator it = c1.begin(); it != c1.end(); ++it)
        ++diff;
    System::Console::WriteLine("end()-begin() = {0}", diff);

    // compute negative difference
    diff = 0;
    for (Myhash_map::iterator it = c1.end(); it != c1.begin(); --it)
        --diff;
    System::Console::WriteLine("begin()-end() = {0}", diff);
    return (0);
    }

[a 1] [b 2] [c 3]
end()-begin() = 3
begin()-end() = -3

hash_map::empty

Tests whether no elements are present.

Syntax

bool empty();

Remarks

The member function returns true for an empty controlled sequence. It's equivalent to size() == 0. You use it to test whether the hash_map is empty.

Example

// cliext_hash_map_empty.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    System::Console::WriteLine("size() = {0}", c1.size());
    System::Console::WriteLine("empty() = {0}", c1.empty());

    // clear the container and reinspect
    c1.clear();
    System::Console::WriteLine("size() = {0}", c1.size());
    System::Console::WriteLine("empty() = {0}", c1.empty());
    return (0);
    }

[a 1] [b 2] [c 3]
size() = 3
empty() = False
size() = 0
empty() = True

hash_map::end

Designates the end of the controlled sequence.

Syntax

iterator end();

Remarks

The member function returns a bidirectional iterator that points just beyond the end of the controlled sequence. You use it to obtain an iterator that designates the end of the controlled sequence; its status doesn't change if the length of the controlled sequence changes.

Example

// cliext_hash_map_end.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect last two items
    Myhash_map::iterator it = c1.end();
    --it;
    --it;
    System::Console::WriteLine("*-- --end() = [{0} {1}]",
        it->first, it->second);
    ++it;
    System::Console::WriteLine("*--end() = [{0} {1}]",
        it->first, it->second);
    return (0);
    }

[a 1] [b 2] [c 3]
*-- --end() = [b 2]
*--end() = [c 3]

hash_map::equal_range

Finds range that matches a specified key.

Syntax

cliext::pair<iterator, iterator> equal_range(key_type key);

Parameters

key
Key value to search for.

Remarks

The member function returns a pair of iterators cliext::pair<iterator, iterator>(lower_bound(key), upper_bound(key)). You use it to determine the range of elements currently in the controlled sequence that match a specified key.

Example

// cliext_hash_map_equal_range.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
typedef Myhash_map::pair_iter_iter Pairii;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // display results of failed search
    Pairii pair1 = c1.equal_range(L'x');
    System::Console::WriteLine("equal_range(L'x') empty = {0}",
        pair1.first == pair1.second);

    // display results of successful search
    pair1 = c1.equal_range(L'b');
    for (; pair1.first != pair1.second; ++pair1.first)
        System::Console::Write("[{0} {1}] ",
            pair1.first->first, pair1.first->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
equal_range(L'x') empty = True
[b 2]

hash_map::erase

Removes elements at specified positions.

Syntax

iterator erase(iterator where);
iterator erase(iterator first, iterator last);
bool erase(key_type key)

Parameters

first
Beginning of range to erase.

key
Key value to erase.

last
End of range to erase.

where
Element to erase.

Remarks

The first member function removes the element of the controlled sequence pointed to by where, and returns an iterator that designates the first element remaining beyond the element removed, or end() if no such element exists. You use it to remove a single element.

The second member function removes the elements of the controlled sequence in the range [first, last), and returns an iterator that designates the first element remaining beyond any elements removed, or end() if no such element exists. You use it to remove zero or more contiguous elements.

The third member function removes any element of the controlled sequence whose key has equivalent ordering to key, and returns a count of the number of elements removed. You use it to remove and count all elements that match a specified key.

Each element erasure takes time proportional to the logarithm of the number of elements in the controlled sequence.

Example

// cliext_hash_map_erase.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    cliext::hash_map<wchar_t, int> c1;
    c1.insert(cliext::hash_map<wchar_t, int>::make_value(L'a', 1));
    c1.insert(cliext::hash_map<wchar_t, int>::make_value(L'b', 2));
    c1.insert(cliext::hash_map<wchar_t, int>::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (cliext::hash_map<wchar_t, int>::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // erase an element and reinspect
    cliext::hash_map<wchar_t, int>::iterator it =
        c1.erase(c1.begin());
    System::Console::WriteLine("erase(begin()) = [{0} {1}]",
        it->first, it->second);

    // add elements and display " b c d e"
    c1.insert(cliext::hash_map<wchar_t, int>::make_value(L'd', 4));
    c1.insert(cliext::hash_map<wchar_t, int>::make_value(L'e', 5));
    for each (cliext::hash_map<wchar_t, int>::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // erase all but end
    it = c1.end();
    it = c1.erase(c1.begin(), --it);
    System::Console::WriteLine("erase(begin(), end()-1) = [{0} {1}]",
        it->first, it->second);
    System::Console::WriteLine("size() = {0}", c1.size());

    // erase end
    System::Console::WriteLine("erase(L'x') = {0}", c1.erase(L'x'));
    System::Console::WriteLine("erase(L'e') = {0}", c1.erase(L'e'));
    return (0);
    }

[a 1] [b 2] [c 3]
erase(begin()) = [b 2]
[b 2] [c 3] [d 4] [e 5]
erase(begin(), end()-1) = [e 5]
size() = 1
erase(L'x') = 0
erase(L'e') = 1

hash_map::find

Finds an element that matches a specified key.

Syntax

iterator find(key_type key);

Parameters

key
Key value to search for.

Remarks

If at least one element in the controlled sequence has equivalent ordering with key, the member function returns an iterator designating one of those elements; otherwise it returns end(). You use it to locate an element currently in the controlled sequence that matches a specified key.

Example

// cliext_hash_map_find.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    System::Console::WriteLine("find {0} = {1}",
        L'A', c1.find(L'A') != c1.end());

    Myhash_map::iterator it = c1.find(L'b');
    System::Console::WriteLine("find {0} = [{1} {2}]",
        L'b', it->first, it->second);

    System::Console::WriteLine("find {0} = {1}",
        L'C', c1.find(L'C') != c1.end());
    return (0);
    }

[a 1] [b 2] [c 3]
find A = False
find b = [b 2]
find C = False

hash_map::generic_container

The type of the generic interface for the container.

Syntax

typedef Microsoft::VisualC::StlClr::
    IHash<GKey, GValue>
    generic_container;

Remarks

The type describes the generic interface for this template container class.

Example

// cliext_hash_map_generic_container.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct a generic container
    Myhash_map::generic_container^ gc1 = %c1;
    for each (Myhash_map::value_type elem in gc1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // modify generic and display original
    gc1->insert(Myhash_map::make_value(L'd', 4));
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // modify original and display generic
    c1.insert(Myhash_map::make_value(L'e', 5));
    for each (Myhash_map::value_type elem in gc1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3] [d 4]
[a 1] [b 2] [c 3] [d 4] [e 5]

hash_map::generic_iterator

The type of an iterator for use with the generic interface for the container.

Syntax

typedef Microsoft::VisualC::StlClr::Generic::
    ContainerBidirectionalIterator<generic_value>
    generic_iterator;

Remarks

The type describes a generic iterator that can be used with the generic interface for this template container class.

Example

// cliext_hash_map_generic_iterator.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct a generic container
    Myhash_map::generic_container^ gc1 = %c1;
    for each (Myhash_map::value_type elem in gc1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // get an element and display it
    Myhash_map::generic_iterator gcit = gc1->begin();
    Myhash_map::generic_value gcval = *gcit;
    System::Console::Write("[{0} {1}] ", gcval->first, gcval->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]
[a 1]

hash_map::generic_reverse_iterator

The type of a reverse iterator for use with the generic interface for the container.

Syntax

typedef Microsoft::VisualC::StlClr::Generic::
    ReverseRandomAccessIterator<generic_value>
    generic_reverse_iterator;

Remarks

The type describes a generic reverse iterator that can be used with the generic interface for this template container class.

Example

// cliext_hash_map_generic_reverse_iterator.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct a generic container
    Myhash_map::generic_container^ gc1 = %c1;
    for each (Myhash_map::value_type elem in gc1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // get an element and display it
    Myhash_map::generic_reverse_iterator gcit = gc1->rbegin();
    Myhash_map::generic_value gcval = *gcit;
    System::Console::WriteLine("[{0} {1}] ", gcval->first, gcval->second);
    return (0);
    }

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]
[c 3]

hash_map::generic_value

The type of an element for use with the generic interface for the container.

Syntax

typedef GValue generic_value;

Remarks

The type describes an object of type GValue that describes the stored element value for use with the generic interface for this template container class.

Example

// cliext_hash_map_generic_value.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct a generic container
    Myhash_map::generic_container^ gc1 = %c1;
    for each (Myhash_map::value_type elem in gc1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // get an element and display it
    Myhash_map::generic_iterator gcit = gc1->begin();
    Myhash_map::generic_value gcval = *gcit;
    System::Console::WriteLine("[{0} {1}] ", gcval->first, gcval->second);
    return (0);
    }

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]
[a 1]

hash_map::hash_delegate

Finds an element that matches a specified key.

Syntax

hasher^ hash_delegate();

Remarks

The member function returns the delegate used to convert a key value to an integer. You use it to hash a key.

Example

// cliext_hash_map_hash_delegate.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    Myhash_map::hasher^ myhash = c1.hash_delegate();

    System::Console::WriteLine("hash(L'a') = {0}", myhash(L'a'));
    System::Console::WriteLine("hash(L'b') = {0}", myhash(L'b'));
    return (0);
    }

hash(L'a') = 1616896120
hash(L'b') = 570892832

hash_map::hash_map

Constructs a container object.

Syntax

hash_map();
explicit hash_map(key_compare^ pred);
hash_map(key_compare^ pred, hasher^ hashfn);
hash_map(hash_map<Key, Mapped>% right);
hash_map(hash_map<Key, Mapped>^ right);
template<typename InIter>
    hash_maphash_map(InIter first, InIter last);
template<typename InIter>
    hash_map(InIter first, InIter last,
        key_compare^ pred);
template<typename InIter>
    hash_map(InIter first, InIter last,
        key_compare^ pred, hasher^ hashfn);
hash_map(System::Collections::Generic::IEnumerable<GValue>^ right);
hash_map(System::Collections::Generic::IEnumerable<GValue>^ right,
    key_compare^ pred);
hash_map(System::Collections::Generic::IEnumerable<GValue>^ right,
    key_compare^ pred, hasher^ hashfn);

Parameters

first
Beginning of range to insert.

hashfn
Hash function for mapping keys to buckets.

last
End of range to insert.

pred
Ordering predicate for the controlled sequence.

right
Object or range to insert.

Remarks

The constructor:

hash_map();

initializes the controlled sequence with no elements, with the default ordering predicate key_compare(), and with the default hash function. You use it to specify an empty initial controlled sequence, with the default ordering predicate and hash function.

The constructor:

explicit hash_map(key_compare^ pred);

initializes the controlled sequence with no elements, with the ordering predicate pred, and with the default hash function. You use it to specify an empty initial controlled sequence, with the specified ordering predicate and the default hash function.

The constructor:

hash_map(key_compare^ pred, hasher^ hashfn);

initializes the controlled sequence with no elements, with the ordering predicate pred, and with the hash function hashfn. You use it to specify an empty initial controlled sequence, with the specified ordering predicate and hash function.

The constructor:

hash_map(hash_map<Key, Mapped>% right);

initializes the controlled sequence with the sequence [right.begin(), right.end()), with the default ordering predicate, and with the default hash function. You use it to specify an initial controlled sequence that is a copy of the sequence controlled by the hash_map object right, with the default ordering predicate and hash function.

The constructor:

hash_map(hash_map<Key, Mapped>^ right);

initializes the controlled sequence with the sequence [right->begin(), right->end()), with the default ordering predicate, and with the default hash function. You use it to specify an initial controlled sequence that is a copy of the sequence controlled by the hash_map object right, with the default ordering predicate and hash function.

The constructor:

template<typename InIter> hash_map(InIter first, InIter last);

initializes the controlled sequence with the sequence [first, last), with the default ordering predicate, and with the default hash function. You use it to make the controlled sequence a copy of another sequence, with the default ordering predicate and hash function.

The constructor:

template<typename InIter> hash_map(InIter first, InIter last, key_compare^ pred);

initializes the controlled sequence with the sequence [first, last), with the ordering predicate pred, and with the default hash function. You use it to make the controlled sequence a copy of another sequence, with the specified ordering predicate and the default hash function.

The constructor:

template<typename InIter> hash_map(InIter first, InIter last, key_compare^ pred, hasher^ hashfn);

initializes the controlled sequence with the sequence [first, last), with the ordering predicate pred, and with the hash function hashfn. You use it to make the controlled sequence a copy of another sequence, with the specified ordering predicate and hash function.

The constructor:

hash_map(System::Collections::Generic::IEnumerable<Key>^ right);

initializes the controlled sequence with the sequence designated by the enumerator right, with the default ordering predicate, and with the default hash function. You use it to make the controlled sequence a copy of another sequence described by an enumerator, with the default ordering predicate and hash function.

The constructor:

hash_map(System::Collections::Generic::IEnumerable<Key>^ right, key_compare^ pred);

initializes the controlled sequence with the sequence designated by the enumerator right, with the ordering predicate pred, and with the default hash function. You use it to make the controlled sequence a copy of another sequence described by an enumerator, with the specified ordering predicate and default hash function.

The constructor:

hash_map(System::Collections::Generic::IEnumerable<Key>^ right, key_compare^ pred, hasher^ hashfn);

initializes the controlled sequence with the sequence designated by the enumerator right, with the ordering predicate pred, and with the hash function hashfn. You use it to make the controlled sequence a copy of another sequence described by an enumerator, with the specified ordering predicate and hash function.

Example

// cliext_hash_map_construct.cpp
// compile with: /clr
#include <cliext/hash_map>

int myfun(wchar_t key)
    { // hash a key
    return (key ^ 0xdeadbeef);
    }

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
// construct an empty container
    Myhash_map c1;
    System::Console::WriteLine("size() = {0}", c1.size());

    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct with an ordering rule
    Myhash_map c2 = cliext::greater_equal<wchar_t>();
    System::Console::WriteLine("size() = {0}", c2.size());

    c2.insert(c1.begin(), c1.end());
    for each (Myhash_map::value_type elem in c2)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct with an ordering rule and hash function
    Myhash_map c2h(cliext::greater_equal<wchar_t>(),
        gcnew Myhash_map::hasher(&myfun));
    System::Console::WriteLine("size() = {0}", c2h.size());

    c2h.insert(c1.begin(), c1.end());
    for each (Myhash_map::value_type elem in c2h)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    System::Console::WriteLine();

    // construct with an iterator range
    Myhash_map c3(c1.begin(), c1.end());
    for each (Myhash_map::value_type elem in c3)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct with an iterator range and an ordering rule
    Myhash_map c4(c1.begin(), c1.end(),
        cliext::greater_equal<wchar_t>());
    for each (Myhash_map::value_type elem in c4)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct with an iterator range and an ordering rule and hash function
    Myhash_map c4h(c1.begin(), c1.end(),
        cliext::greater_equal<wchar_t>(),
        gcnew Myhash_map::hasher(&myfun));
    for each (Myhash_map::value_type elem in c4h)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    System::Console::WriteLine();

    // construct with an enumeration
    Myhash_map c5(   // NOTE: cast is not needed
        (System::Collections::Generic::IEnumerable<
            Myhash_map::value_type>^)%c3);
    for each (Myhash_map::value_type elem in c5)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct with an enumeration and an ordering rule
    Myhash_map c6(   // NOTE: cast is not needed
        (System::Collections::Generic::IEnumerable<
            Myhash_map::value_type>^)%c3,
                cliext::greater_equal<wchar_t>());
    for each (Myhash_map::value_type elem in c6)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct with an enumeration and an ordering rule and hash function
    Myhash_map c6h(   // NOTE: cast is not needed
        (System::Collections::Generic::IEnumerable<
            Myhash_map::value_type>^)%c3,
                cliext::greater_equal<wchar_t>(),
                gcnew Myhash_map::hasher(&myfun));
    for each (Myhash_map::value_type elem in c6h)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    System::Console::WriteLine();

    // construct by copying another container
    Myhash_map c7(c4);
    for each (Myhash_map::value_type elem in c7)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct by copying a container handle
    Myhash_map c8(%c3);
    for each (Myhash_map::value_type elem in c8)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

size() = 0
[a 1] [b 2] [c 3]
size() = 0
[a 1] [b 2] [c 3]
size() = 0
[c 3] [b 2] [a 1]

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]
[c 3] [b 2] [a 1]

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]
[c 3] [b 2] [a 1]

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]

hash_map::hasher

The hashing delegate for a key.

Syntax

Microsoft::VisualC::StlClr::UnaryDelegate<GKey, int>
    hasher;

Remarks

The type describes a delegate that converts a key value to an integer.

Example

// cliext_hash_map_hasher.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    Myhash_map::hasher^ myhash = c1.hash_delegate();

    System::Console::WriteLine("hash(L'a') = {0}", myhash(L'a'));
    System::Console::WriteLine("hash(L'b') = {0}", myhash(L'b'));
    return (0);
    }

hash(L'a') = 1616896120
hash(L'b') = 570892832

hash_map::insert

Adds elements.

Syntax

cliext::pair<iterator, bool> insert(value_type val);
iterator insert(iterator where, value_type val);
template<typename InIter>
    void insert(InIter first, InIter last);
void insert(System::Collections::Generic::IEnumerable<value_type>^ right);

Parameters

first
Beginning of range to insert.

last
End of range to insert.

right
Enumeration to insert.

val
Key value to insert.

where
Where in container to insert (hint only).

Remarks

Each of the member functions inserts a sequence specified by the remaining operands.

The first member function endeavors to insert an element with value val, and returns a pair of values X. If X.second is true, X.first designates the newly inserted element; otherwise X.first designates an element with equivalent ordering that already exists and no new element is inserted. You use it to insert a single element.

The second member function inserts an element with value val, using where as a hint (to improve performance), and returns an iterator that designates the newly inserted element. You use it to insert a single element that might be next to an element you know.

The third member function inserts the sequence [first, last). You use it to insert zero or more elements copied from another sequence.

The fourth member function inserts the sequence designated by the right. You use it to insert a sequence described by an enumerator.

Each element insertion takes time proportional to the logarithm of the number of elements in the controlled sequence. Insertion can occur in amortized constant time, however, given a hint that designates an element next to the insertion point.

Example

// cliext_hash_map_insert.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
typedef Myhash_map::pair_iter_bool Pairib;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // insert a single value, unique and duplicate
    Pairib pair1 =
        c1.insert(Myhash_map::make_value(L'x', 24));
    System::Console::WriteLine("insert([L'x' 24]) = [{0} {1}] {2}",
        pair1.first->first, pair1.first->second, pair1.second);

    pair1 = c1.insert(Myhash_map::make_value(L'b', 2));
    System::Console::WriteLine("insert([L'b' 2]) = [{0} {1}] {2}",
        pair1.first->first, pair1.first->second, pair1.second);

    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // insert a single value with hint
    Myhash_map::iterator it =
        c1.insert(c1.begin(), Myhash_map::make_value(L'y', 25));
    System::Console::WriteLine("insert(begin(), [L'y' 25]) = [{0} {1}]",
        it->first, it->second);
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // insert an iterator range
    Myhash_map c2;
    it = c1.end();
    c2.insert(c1.begin(), --it);
    for each (Myhash_map::value_type elem in c2)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // insert an enumeration
    Myhash_map c3;
    c3.insert(   // NOTE: cast is not needed
        (System::Collections::Generic::
            IEnumerable<Myhash_map::value_type>^)%c1);
    for each (Myhash_map::value_type elem in c3)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
insert([L'x' 24]) = [x 24] True
insert([L'b' 2]) = [b 2] False
[a 1] [b 2] [c 3] [x 24]
insert(begin(), [L'y' 25]) = [y 25]
[a 1] [b 2] [c 3] [x 24] [y 25]
[a 1] [b 2] [c 3] [x 24]
[a 1] [b 2] [c 3] [x 24] [y 25]

hash_map::iterator

The type of an iterator for the controlled sequence.

Syntax

typedef T1 iterator;

Remarks

The type describes an object of unspecified type T1 that can serve as a bidirectional iterator for the controlled sequence.

Example

// cliext_hash_map_iterator.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    Myhash_map::iterator it = c1.begin();
    for (; it != c1.end(); ++it)
        System::Console::Write("[{0} {1}] ", it->first, it->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]

hash_map::key_comp

Copies the ordering delegate for two keys.

Syntax

key_compare^key_comp();

Remarks

The member function returns the ordering delegate used to order the controlled sequence. You use it to compare two keys.

Example

// cliext_hash_map_key_comp.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    Myhash_map::key_compare^ kcomp = c1.key_comp();

    System::Console::WriteLine("compare(L'a', L'a') = {0}",
        kcomp(L'a', L'a'));
    System::Console::WriteLine("compare(L'a', L'b') = {0}",
        kcomp(L'a', L'b'));
    System::Console::WriteLine("compare(L'b', L'a') = {0}",
        kcomp(L'b', L'a'));
    System::Console::WriteLine();

    // test a different ordering rule
    Myhash_map c2 = cliext::greater<wchar_t>();
    kcomp = c2.key_comp();

    System::Console::WriteLine("compare(L'a', L'a') = {0}",
        kcomp(L'a', L'a'));
    System::Console::WriteLine("compare(L'a', L'b') = {0}",
        kcomp(L'a', L'b'));
    System::Console::WriteLine("compare(L'b', L'a') = {0}",
        kcomp(L'b', L'a'));
    return (0);
    }

compare(L'a', L'a') = True
compare(L'a', L'b') = True
compare(L'b', L'a') = False

compare(L'a', L'a') = False
compare(L'a', L'b') = False
compare(L'b', L'a') = True

hash_map::key_compare

The ordering delegate for two keys.

Syntax

Microsoft::VisualC::StlClr::BinaryDelegate<GKey, GKey, bool>
    key_compare;

Remarks

The type is a synonym for the delegate that determines the ordering of its key arguments.

Example

// cliext_hash_map_key_compare.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    Myhash_map::key_compare^ kcomp = c1.key_comp();

    System::Console::WriteLine("compare(L'a', L'a') = {0}",
        kcomp(L'a', L'a'));
    System::Console::WriteLine("compare(L'a', L'b') = {0}",
        kcomp(L'a', L'b'));
    System::Console::WriteLine("compare(L'b', L'a') = {0}",
        kcomp(L'b', L'a'));
    System::Console::WriteLine();

    // test a different ordering rule
    Myhash_map c2 = cliext::greater<wchar_t>();
    kcomp = c2.key_comp();

    System::Console::WriteLine("compare(L'a', L'a') = {0}",
        kcomp(L'a', L'a'));
    System::Console::WriteLine("compare(L'a', L'b') = {0}",
        kcomp(L'a', L'b'));
    System::Console::WriteLine("compare(L'b', L'a') = {0}",
        kcomp(L'b', L'a'));
    return (0);
    }

compare(L'a', L'a') = True
compare(L'a', L'b') = True
compare(L'b', L'a') = False

compare(L'a', L'a') = False
compare(L'a', L'b') = False
compare(L'b', L'a') = True

hash_map::key_type

The type of an ordering key.

Syntax

typedef Key key_type;

Remarks

The type is a synonym for the template parameter Key.

Example

// cliext_hash_map_key_type.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]" using key_type
    for (Myhash_map::iterator it = c1.begin(); it != c1.end(); ++it)
        {   // store element in key_type object
        Myhash_map::key_type val = it->first;

        System::Console::Write("{0} ", val);
        }
    System::Console::WriteLine();
    return (0);
    }

a b c

hash_map::load_factor

Counts the average elements per bucket.

Syntax

float load_factor();

Remarks

The member function returns (float)size() / bucket_count(). You use it to determine the average bucket size.

Example

// cliext_hash_map_load_factor.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1 = gcnew Myhash_map;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect current parameters
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // change max_load_factor and redisplay
    c1.max_load_factor(0.25f);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // rehash and redisplay
    c1.rehash(100);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    return (0);
    }

[a 1] [b 2] [c 3]
bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 4

bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 0.25

bucket_count() = 128
load_factor() = 0.0234375
max_load_factor() = 0.25

hash_map::lower_bound

Finds beginning of range that matches a specified key.

Syntax

iterator lower_bound(key_type key);

Parameters

key
Key value to search for.

Remarks

The member function determines the first element X in the controlled sequence that hashes to the same bucket as key and has equivalent ordering to key. If no such element exists, it returns end(); otherwise it returns an iterator that designates X. You use it to locate the beginning of a sequence of elements currently in the controlled sequence that match a specified key.

Example

// cliext_hash_map_lower_bound.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    System::Console::WriteLine("lower_bound(L'x')==end() = {0}",
        c1.lower_bound(L'x') == c1.end());

    Myhash_map::iterator it = c1.lower_bound(L'a');
    System::Console::WriteLine("*lower_bound(L'a') = [{0} {1}]",
        it->first, it->second);
    it = c1.lower_bound(L'b');
    System::Console::WriteLine("*lower_bound(L'b') = [{0} {1}]",
        it->first, it->second);
    return (0);
    }

[a 1] [b 2] [c 3]
lower_bound(L'x')==end() = True
*lower_bound(L'a') = [a 1]
*lower_bound(L'b') = [b 2]

hash_map::make_value

Constructs a value object.

Syntax

static value_type make_value(key_type key, mapped_type mapped);

Parameters

key
Key value to use.

mapped
Mapped value to search for.

Remarks

The member function returns a value_type object whose key is key and whose mapped value is mapped. You use it to compose an object suitable for use with several other member functions.

Example

// cliext_hash_map_make_value.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]

hash_map::mapped_type

The type of a mapped value associated with each key.

Syntax

typedef Mapped mapped_type;

Remarks

The type is a synonym for the template parameter Mapped.

Example

// cliext_hash_map_mapped_type.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]" using mapped_type
    for (Myhash_map::iterator it = c1.begin(); it != c1.end(); ++it)
        {   // store element in mapped_type object
        Myhash_map::mapped_type val = it->second;

        System::Console::Write("{0} ", val);
        }
    System::Console::WriteLine();
    return (0);
    }

1 2 3

hash_map::max_load_factor

Gets or sets the maximum elements per bucket.

Syntax

float max_load_factor();
void max_load_factor(float new_factor);

Parameters

new_factor
New maximum load factor to store.

Remarks

The first member function returns the current stored maximum load factor. You use it to determine the maximum average bucket size.

The second member function replaces the store maximum load factor with new_factor. No automatic rehashing occurs until a subsequent insert.

Example

// cliext_hash_map_max_load_factor.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1 = gcnew Myhash_map;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect current parameters
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // change max_load_factor and redisplay
    c1.max_load_factor(0.25f);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // rehash and redisplay
    c1.rehash(100);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    return (0);
    }

[a 1] [b 2] [c 3]
bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 4

bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 0.25

bucket_count() = 128
load_factor() = 0.0234375
max_load_factor() = 0.25

hash_map::operator=

Replaces the controlled sequence.

Syntax

hash_map<Key, Mapped>% operator=(hash_map<Key, Mapped>% right);

Parameters

right
Container to copy.

Remarks

The member operator copies right to the object, then returns *this. You use it to replace the controlled sequence with a copy of the controlled sequence in right.

Example

// cliext_hash_map_operator_as.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // assign to a new container
    Myhash_map c2;
    c2 = c1;
// display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c2)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
[a 1] [b 2] [c 3]

hash_map::operator[]

Maps a key to its associated mapped value.

Syntax

mapped_type operator[](key_type key);

Parameters

key
Key value to search for.

Remarks

The member functions endeavors to find an element with equivalent ordering to key. If it finds one, it returns the associated mapped value; otherwise, it inserts value_type(key, mapped_type()) and returns the associated (default) mapped value. You use it to look up a mapped value given its associated key, or to ensure that an entry exists for the key if none is found.

Example

// cliext_hash_map_operator_sub.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    System::Console::WriteLine("c1[{0}] = {1}",
        L'A', c1[L'A']);
    System::Console::WriteLine("c1[{0}] = {1}",
        L'b', c1[L'b']);

    // redisplay altered contents
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // alter mapped values and redisplay
    c1[L'A'] = 10;
    c1[L'c'] = 13;
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
c1[A] = 0
c1[b] = 2
[a 1] [A 0] [b 2] [c 3]
[a 1] [A 10] [b 2] [c 13]

hash_map::rbegin

Designates the beginning of the reversed controlled sequence.

Syntax

reverse_iterator rbegin();

Remarks

The member function returns a reverse iterator that designates the last element of the controlled sequence, or just beyond the beginning of an empty sequence. Hence, it designates the beginning of the reverse sequence. You use it to obtain an iterator that designates the current beginning of the controlled sequence seen in reverse order, but its status can change if the length of the controlled sequence changes.

Example

// cliext_hash_map_rbegin.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect first two items in reversed sequence
    Myhash_map::reverse_iterator rit = c1.rbegin();
    System::Console::WriteLine("*rbegin() = [{0} {1}]",
        rit->first, rit->second);
    ++rit;
    System::Console::WriteLine("*++rbegin() = [{0} {1}]",
        rit->first, rit->second);
    return (0);
    }

[a 1] [b 2] [c 3]
*rbegin() = [c 3]
*++rbegin() = [b 2]

hash_map::reference

The type of a reference to an element.

Syntax

typedef value_type% reference;

Remarks

The type describes a reference to an element.

Example

// cliext_hash_map_reference.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    Myhash_map::iterator it = c1.begin();
    for (; it != c1.end(); ++it)
        {   // get a reference to an element
        Myhash_map::reference ref = *it;
        System::Console::Write("[{0} {1}] ", ref->first, ref->second);
        }
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]

hash_map::rehash

Rebuilds the hash table.

Syntax

void rehash();

Remarks

The member function rebuilds the hash table, ensuring that load_factor() <= max_load_factor(). Otherwise, the hash table increases in size only as needed after an insertion. (It never automatically decreases in size.) You use it to adjust the size of the hash table.

Example

// cliext_hash_map_rehash.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1 = gcnew Myhash_map;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect current parameters
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // change max_load_factor and redisplay
    c1.max_load_factor(0.25f);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    System::Console::WriteLine();

    // rehash and redisplay
    c1.rehash(100);
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count());
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor());
    System::Console::WriteLine("max_load_factor() = {0}",
        c1.max_load_factor());
    return (0);
    }

[a 1] [b 2] [c 3]
bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 4

bucket_count() = 16
load_factor() = 0.1875
max_load_factor() = 0.25

bucket_count() = 128
load_factor() = 0.0234375
max_load_factor() = 0.25

hash_map::rend

Designates the end of the reversed controlled sequence.

Syntax

reverse_iterator rend();

Remarks

The member function returns a reverse iterator that points just beyond the beginning of the controlled sequence. Hence, it designates the end of the reverse sequence. You use it to obtain an iterator that designates the current end of the controlled sequence seen in reverse order, but its status can change if the length of the controlled sequence changes.

Example

// cliext_hash_map_rend.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // inspect first two items in reversed sequence
    Myhash_map::reverse_iterator rit = c1.rend();
    --rit;
    --rit;
    System::Console::WriteLine("*-- --rend() = [{0} {1}]",
        rit->first, rit->second);
    ++rit;
    System::Console::WriteLine("*--rend() = [{0} {1}]",
        rit->first, rit->second);
    return (0);
    }

[a 1] [b 2] [c 3]
*-- --rend() = [b 2]
*--rend() = [a 1]

hash_map::reverse_iterator

The type of a reverse iterator for the controlled sequence.

Syntax

typedef T3 reverse_iterator;

Remarks

The type describes an object of unspecified type T3 that can serve as a reverse iterator for the controlled sequence.

Example

// cliext_hash_map_reverse_iterator.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]" reversed
    Myhash_map::reverse_iterator rit = c1.rbegin();
    for (; rit != c1.rend(); ++rit)
        System::Console::Write("[{0} {1}] ", rit->first, rit->second);
    System::Console::WriteLine();
    return (0);
    }

[c 3] [b 2] [a 1]

hash_map::size

Counts the number of elements.

Syntax

size_type size();

Remarks

The member function returns the length of the controlled sequence. You use it to determine the number of elements currently in the controlled sequence. If all you care about is whether the sequence has nonzero size, see hash_map::empty.

Example

// cliext_hash_map_size.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // clear the container and reinspect
    c1.clear();
    System::Console::WriteLine("size() = {0} after clearing", c1.size());

    // add elements and clear again
    c1.insert(Myhash_map::make_value(L'd', 4));
    c1.insert(Myhash_map::make_value(L'e', 5));
    System::Console::WriteLine("size() = {0} after adding 2", c1.size());
    return (0);
    }

[a 1] [b 2] [c 3]
size() = 0 after clearing
size() = 2 after adding 2

hash_map::size_type

The type of a signed distance between two elements.

Syntax

typedef int size_type;

Remarks

The type describes a non-negative element count.

Example

// cliext_hash_map_size_type.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // compute positive difference
    Myhash_map::size_type diff = 0;
    for (Myhash_map::iterator it = c1.begin(); it != c1.end(); ++it)
        ++diff;
    System::Console::WriteLine("end()-begin() = {0}", diff);
    return (0);
    }

[a 1] [b 2] [c 3]
end()-begin() = 3

hash_map::swap

Swaps the contents of two containers.

Syntax

void swap(hash_map<Key, Mapped>% right);

Parameters

right
Container to swap contents with.

Remarks

The member function swaps the controlled sequences between this and right. It does so in constant time and it throws no exceptions. You use it as a quick way to exchange the contents of two containers.

Example

// cliext_hash_map_swap.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // construct another container with repetition of values
    Myhash_map c2;
    c2.insert(Myhash_map::make_value(L'd', 4));
    c2.insert(Myhash_map::make_value(L'e', 5));
    c2.insert(Myhash_map::make_value(L'f', 6));
    for each (Myhash_map::value_type elem in c2)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // swap and redisplay
    c1.swap(c2);
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    for each (Myhash_map::value_type elem in c2)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]
[d 4] [e 5] [f 6]
[d 4] [e 5] [f 6]
[a 1] [b 2] [c 3]

hash_map::to_array

Copies the controlled sequence to a new array.

Syntax

cli::array<value_type>^ to_array();

Remarks

The member function returns an array containing the controlled sequence. You use it to obtain a copy of the controlled sequence in array form.

Example

// cliext_hash_map_to_array.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // copy the container and modify it
    cli::array<Myhash_map::value_type>^ a1 = c1.to_array();

    c1.insert(Myhash_map::make_value(L'd', 4));
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    // display the earlier array copy
    for each (Myhash_map::value_type elem in a1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3] [d 4]
[a 1] [b 2] [c 3]

hash_map::upper_bound

Finds end of range that matches a specified key.

Syntax

iterator upper_bound(key_type key);

Parameters

key
Key value to search for.

Remarks

The member function determines the last element X in the controlled sequence that hashes to the same bucket as key and has equivalent ordering to key. If no such element exists, or if X is the last element in the controlled sequence, it returns end(); otherwise it returns an iterator that designates the first element beyond X. You use it to locate the end of a sequence of elements currently in the controlled sequence that match a specified key.

Example

// cliext_hash_map_upper_bound.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]"
    for each (Myhash_map::value_type elem in c1)
        System::Console::Write("[{0} {1}] ", elem->first, elem->second);
    System::Console::WriteLine();

    System::Console::WriteLine("upper_bound(L'x')==end() = {0}",
        c1.upper_bound(L'x') == c1.end());

    Myhash_map::iterator it = c1.upper_bound(L'a');
    System::Console::WriteLine("*upper_bound(L'a') = [{0} {1}]",
        it->first, it->second);
    it = c1.upper_bound(L'b');
    System::Console::WriteLine("*upper_bound(L'b') = [{0} {1}]",
        it->first, it->second);
    return (0);
    }

[a 1] [b 2] [c 3]
upper_bound(L'x')==end() = True
*upper_bound(L'a') = [b 2]
*upper_bound(L'b') = [c 3]

hash_map::value_comp

Copies the ordering delegate for two element values.

Syntax

value_compare^ value_comp();

Remarks

The member function returns the ordering delegate used to order the controlled sequence. You use it to compare two element values.

Example

// cliext_hash_map_value_comp.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    Myhash_map::value_compare^ kcomp = c1.value_comp();

    System::Console::WriteLine("compare([L'a', 1], [L'a', 1]) = {0}",
        kcomp(Myhash_map::make_value(L'a', 1),
            Myhash_map::make_value(L'a', 1)));
    System::Console::WriteLine("compare([L'a', 1], [L'b', 2]) = {0}",
        kcomp(Myhash_map::make_value(L'a', 1),
            Myhash_map::make_value(L'b', 2)));
    System::Console::WriteLine("compare([L'b', 2], [L'a', 1]) = {0}",
        kcomp(Myhash_map::make_value(L'b', 2),
            Myhash_map::make_value(L'a', 1)));
    System::Console::WriteLine();
    return (0);
    }

compare([L'a', 1], [L'a', 1]) = True
compare([L'a', 1], [L'b', 2]) = True
compare([L'b', 2], [L'a', 1]) = False

hash_map::value_compare

The ordering delegate for two element values.

Syntax

Microsoft::VisualC::StlClr::BinaryDelegate<generic_value, generic_value, bool>
    value_compare;

Remarks

The type is a synonym for the delegate that determines the ordering of its value arguments.

Example

// cliext_hash_map_value_compare.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    Myhash_map::value_compare^ kcomp = c1.value_comp();

    System::Console::WriteLine("compare([L'a', 1], [L'a', 1]) = {0}",
        kcomp(Myhash_map::make_value(L'a', 1),
            Myhash_map::make_value(L'a', 1)));
    System::Console::WriteLine("compare([L'a', 1], [L'b', 2]) = {0}",
        kcomp(Myhash_map::make_value(L'a', 1),
            Myhash_map::make_value(L'b', 2)));
    System::Console::WriteLine("compare([L'b', 2], [L'a', 1]) = {0}",
        kcomp(Myhash_map::make_value(L'b', 2),
            Myhash_map::make_value(L'a', 1)));
    System::Console::WriteLine();
    return (0);
    }

compare([L'a', 1], [L'a', 1]) = True
compare([L'a', 1], [L'b', 2]) = True
compare([L'b', 2], [L'a', 1]) = False

hash_map::value_type

The type of an element.

Syntax

typedef generic_value value_type;

Remarks

The type is a synonym for generic_value.

Example

// cliext_hash_map_value_type.cpp
// compile with: /clr
#include <cliext/hash_map>

typedef cliext::hash_map<wchar_t, int> Myhash_map;
int main()
    {
    Myhash_map c1;
    c1.insert(Myhash_map::make_value(L'a', 1));
    c1.insert(Myhash_map::make_value(L'b', 2));
    c1.insert(Myhash_map::make_value(L'c', 3));

    // display contents " [a 1] [b 2] [c 3]" using value_type
    for (Myhash_map::iterator it = c1.begin(); it != c1.end(); ++it)
        {   // store element in value_type object
        Myhash_map::value_type val = *it;
        System::Console::Write("[{0} {1}] ", val->first, val->second);
        }
    System::Console::WriteLine();
    return (0);
    }

[a 1] [b 2] [c 3]