array Class (STL)

Articolo
01/02/2018

The latest version of this topic can be found at array Class (C++ Standard Library)| Microsoft Docs.

Describes an object that controls a sequence of length N of elements of type Ty. The sequence is stored as an array of Ty, contained in the array<Ty, N> object.

Syntax

template <class Ty, std::size_t N>  
class array;

Parameters

Parameter	Description
`Ty`	The type of an element.
`N`	The number of elements.

Members

Type Definition	Description
array::const_iterator	The type of a constant iterator for the controlled sequence.
array::const_pointer	The type of a constant pointer to an element.
array::const_reference	The type of a constant reference to an element.
array::const_reverse_iterator	The type of a constant reverse iterator for the controlled sequence.
array::difference_type	The type of a signed distance between two elements.
array::iterator	The type of an iterator for the controlled sequence.
array::pointer	The type of a pointer to an element.
array::reference	The type of a reference to an element.
array::reverse_iterator	The type of a reverse iterator for the controlled sequence.
array::size_type	The type of an unsigned distance between two elements.
array::value_type	The type of an element.

Member Function	Description
array::array	Constructs an array object.
array::assign	Replaces all elements.
array::at	Accesses an element at a specified position.
array::back	Accesses the last element.
array::begin	Designates the beginning of the controlled sequence.
array::cbegin	Returns a random-access const iterator to the first element in the array.
array::cend	Returns a random-access const iterator that points just beyond the end of the array.
array::crbegin	Returns a const iterator to the first element in a reversed array.
array::crend	Returns a const iterator to the end of a reversed array.
array::data	Gets the address of the first element.
array::empty	Tests whether elements are present.
array::end	Designates the end of the controlled sequence.
array::fill	Replaces all elements with a specified value.
array::front	Accesses the first element.
array::max_size	Counts the number of elements.
array::rbegin	Designates the beginning of the reversed controlled sequence.
array::rend	Designates the end of the reversed controlled sequence.
array::size	Counts the number of elements.
array::swap	Swaps the contents of two containers.

Operator	Description
array::operator=	Replaces the controlled sequence.
array::operator[]	Accesses an element at a specified position.

Remarks

The type has a default constructor array() and a default assignment operator operator=, and satisfies the requirements for an aggregate. Therefore, objects of type array<Ty, N> can be initialized by using an aggregate initializer. For example,

array<int, 4> ai = { 1, 2, 3 };

creates the object ai that holds four integer values, initializes the first three elements to the values 1, 2, and 3, respectively, and initializes the fourth element to 0.

Requirements

Header: <array>

Namespace: std

array::array

Constructs an array object.

array();

array(const array& right);

Parameters

right
Object or range to insert.

Remarks

The constructor:

array();

leaves the controlled sequence uninitialized (or default initialized). You use it to specify an uninitialized controlled sequence.

The constructor:

array(const array& right);

initializes the controlled sequence with the sequence [``right``.array::begin(), right``.array::end()). You use it to specify an initial controlled sequence that is a copy of the sequence controlled by the array object right.

Example

// std_tr1__array__array_array.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    Myarray c1(c0);   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c1.begin();   
        it != c1.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0 1 2 3

array::assign

Replaces all elements.

void assign(const Ty& val);

Parameters

val
The value to assign.

Remarks

The member function replaces the sequence controlled by *this with a repetition of N elements of value val.

Example

// std_tr1__array__array_assign.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    Myarray c1;   
    c1.assign(4);   
  
// display contents " 4 4 4 4"   
    for (Myarray::const_iterator it = c1.begin();   
        it != c1.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
4 4 4 4

array::at

Accesses an element at a specified position.

reference at(size_type off);

constexpr const_reference at(size_type off) const;

Parameters

off
Position of element to access.

Remarks

The member functions return a reference to the element of the controlled sequence at position off. If that position is invalid, the function throws an object of class out_of_range.

Example

// std__array__array_at.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display odd elements " 1 3"   
    std::cout << " " << c0.at(1);   
    std::cout << " " << c0.at(3);   
    std::cout << std::endl;   
  
    return (0);   
    }

array::back

Accesses the last element.

reference back();

constexpr const_reference back() const;

Remarks

The member functions return a reference to the last element of the controlled sequence, which must be non-empty.

Example

// std__array__array_back.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display last element " 3"   
    std::cout << " " << c0.back();   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
3

array::begin

Designates the beginning of the controlled sequence.

iterator begin() noexcept;  
const_iterator begin() const noexcept;

Remarks

The member functions return a random-access iterator that points at the first element of the sequence (or just beyond the end of an empty sequence).

Example

// std_tr1__array__array_begin.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::iterator it2 = c0.begin();   
    std::cout << " " << *it2;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::cbegin

Returns a const iterator that addresses the first element in the range.

const_iterator cbegin() const noexcept;

Return Value

A const random-access iterator that points at the first element of the range, or the location just beyond the end of an empty range (for an empty range, cbegin() == cend()).

Remarks

With the return value of cbegin, the elements in the range cannot be modified.

You can use this member function in place of the begin() member function to guarantee that the return value is const_iterator. Typically, it's used in conjunction with the auto type deduction keyword, as shown in the following example. In the example, consider Container to be a modifiable (non- const) container of any kind that supports begin() and cbegin().

 
auto i1 = Container.begin();
// i1 is Container<T>::iterator   
auto i2 = Container.cbegin();

// i2 is Container<T>::const_iterator

array::cend

Returns a const iterator that addresses the location just beyond the last element in a range.

const_iterator cend() const noexcept;

Return Value

A random-access iterator that points just beyond the end of the range.

Remarks

cend is used to test whether an iterator has passed the end of its range.

You can use this member function in place of the end() member function to guarantee that the return value is const_iterator. Typically, it's used in conjunction with the auto type deduction keyword, as shown in the following example. In the example, consider Container to be a modifiable (non- const) container of any kind that supports end() and cend().

 
auto i1 = Container.end();
// i1 is Container<T>::iterator   
auto i2 = Container.cend();

// i2 is Container<T>::const_iterator

The value returned by cend should not be dereferenced.

array::const_iterator

The type of a constant iterator for the controlled sequence.

typedef implementation-defined const_iterator;

Remarks

The type describes an object that can serve as a constant random-access iterator for the controlled sequence.

Example

  
// std__array__array_const_iterator.cpp  
// compile with: /EHsc /W4  
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> MyArray;   
  
int main()   
{   
    MyArray c0 = {0, 1, 2, 3};   
  
    // display contents " 0 1 2 3"   
    std::cout << "it1:";  
    for ( MyArray::const_iterator it1 = c0.begin();   
          it1 != c0.end();   
          ++it1 ) {  
       std::cout << " " << *it1;   
    }  
    std::cout << std::endl;   
  
    // display first element " 0"   
    MyArray::const_iterator it2 = c0.begin();   
    std::cout << "it2:";  
    std::cout << " " << *it2;   
    std::cout << std::endl;   
  
    return (0);   
}

it1: 0 1 2 3                                  
  
it2: 0

array::const_pointer

The type of a constant pointer to an element.

typedef const Ty *const_pointer;

Remarks

The type describes an object that can serve as a constant pointer to elements of the sequence.

Example

// std_tr1__array__array_const_pointer.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::const_pointer ptr = &*c0.begin();   
    std::cout << " " << *ptr;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::const_reference

The type of a constant reference to an element.

typedef const Ty& const_reference;

Remarks

The type describes an object that can serve as a constant reference to an element of the controlled sequence.

Example

// std_tr1__array__array_const_reference.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::const_reference ref = *c0.begin();   
    std::cout << " " << ref;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::const_reverse_iterator

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

typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

Remarks

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

Example

// std_tr1__array__array_const_reverse_iterator.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display last element " 3"   
    Myarray::const_reverse_iterator it2 = c0.rbegin();   
    std::cout << " " << *it2;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
3

array::crbegin

Returns a const iterator to the first element in a reversed array.

const_reverse_iterator crbegin() const;

Return Value

A const reverse random-access iterator addressing the first element in a reversed array or addressing what had been the last element in the unreversed array.

Remarks

With the return value of crbegin, the array object cannot be modified.

Example

// array_crbegin.cpp  
// compile with: /EHsc  
#include <array>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;     
   array<int, 2> v1 = {1, 2};  
   array<int, 2>::iterator v1_Iter;  
   array<int, 2>::const_reverse_iterator v1_rIter;  
  
   v1_Iter = v1.begin( );  
   cout << "The first element of array is "  
        << *v1_Iter << "." << endl;  
  
   v1_rIter = v1.crbegin( );  
   cout << "The first element of the reversed array is "  
        << *v1_rIter << "." << endl;  
}

The first element of array is 1.  
The first element of the reversed array is 2.

array::crend

Returns a const iterator that addresses the location succeeding the last element in a reversed array.

const_reverse_iterator crend() const noexcept;

Return Value

A const reverse random-access iterator that addresses the location succeeding the last element in a reversed array (the location that had preceded the first element in the unreversed array).

Remarks

crend is used with a reversed array just as array::cend is used with a array.

With the return value of crend (suitably decremented), the array object cannot be modified.

crend can be used to test to whether a reverse iterator has reached the end of its array.

The value returned by crend should not be dereferenced.

Example

// array_crend.cpp  
// compile with: /EHsc  
#include <array>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;     
   array<int, 2> v1 = {1, 2};  
   array<int, 2>::const_reverse_iterator v1_rIter;  
  
   for ( v1_rIter = v1.rbegin( ) ; v1_rIter != v1.rend( ) ; v1_rIter++ )  
      cout << *v1_rIter << endl;  
}

2  
1

array::data

Gets the address of the first element.

Ty *data
();

const Ty *data
() const;

Remarks

The member functions return the address of the first element in the controlled sequence.

Example

// std_tr1__array__array_data.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::pointer ptr = c0.data();   
    std::cout << " " << *ptr;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::difference_type

The type of a signed distance between two elements.

typedef std::ptrdiff_t difference_type;

Remarks

The signed integer type describes an object that can represent the difference between the addresses of any two elements in the controlled sequence. It is a synonym for the type std::ptrdiff_t.

Example

// std_tr1__array__array_difference_type.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display distance first-last " -4"   
    Myarray::difference_type diff = c0.begin() - c0.end();   
    std::cout << " " << diff;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
-4

array::empty

Tests whether no elements are present.

constexpr bool empty() const;

Remarks

The member function returns true only if N == 0.

Example

// std_tr1__array__array_empty.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display whether c0 is empty " false"   
    std::cout << std::boolalpha << " " << c0.empty();   
    std::cout << std::endl;   
  
    std::array<int, 0> c1;   
  
// display whether c1 is empty " true"   
    std::cout << std::boolalpha << " " << c1.empty();   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
false  
true

array::end

Designates the end of the controlled sequence.

reference end();

const_reference end() const;

Remarks

The member functions return a random-access iterator that points just beyond the end of the sequence.

Example

// std_tr1__array__array_end.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display last element " 3"   
    Myarray::iterator it2 = c0.end();   
    std::cout << " " << *--it2;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
3

array::fill

Erases a array and copies the specified elements to the empty array.

void fill(const Type& val);

Parameters

Parameter	Description
`val`	The value of the element being inserted into the array.

Remarks

fill replaces each element of the array with the specified value.

Example

// array_fill.cpp  
// compile with: /EHsc  
#include <array>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   array<int, 2> v1 = {1, 2};  
   array<int, 2>::iterator iter;  
  
   cout << "v1 = " ;  
   for (iter = v1.begin(); iter != v1.end(); iter++)  
      cout << *iter << " ";  
   cout << endl;  
  
   v1.fill(3);  
   cout << "v1 = " ;  
   for (iter = v1.begin(); iter != v1.end(); iter++)  
      cout << *iter << " ";  
   cout << endl;  
}

array::front

Accesses the first element.

reference front();

constexpr const_reference front() const;

Remarks

The member functions return a reference to the first element of the controlled sequence, which must be non-empty.

Example

// std_tr1__array__array_front.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    std::cout << " " << c0.front();   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::iterator

The type of an iterator for the controlled sequence.

typedef implementation-defined iterator;

Remarks

The type describes an object that can serve as a random-access iterator for the controlled sequence.

Example

  
// std__array__array_iterator.cpp   
// compile with: /EHsc /W4  
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> MyArray;   
  
int main()   
{   
    MyArray c0 = {0, 1, 2, 3};   
  
    // display contents " 0 1 2 3"   
    std::cout << "it1:";  
    for ( MyArray::iterator it1 = c0.begin();   
          it1 != c0.end();   
          ++it1 ) {  
       std::cout << " " << *it1;   
    }  
    std::cout << std::endl;   
  
    // display first element " 0"   
    MyArray::iterator it2 = c0.begin();   
    std::cout << "it2:";  
    std::cout << " " << *it2;   
    std::cout << std::endl;   
  
    return (0);   
}

it1: 0 1 2 3                                  
  
it2: 0

array::max_size

Counts the number of elements.

constexpr size_type max_size() const;

Remarks

The member function returns N.

Example

// std__array__array_max_size.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display (maximum) size " 4"   
    std::cout << " " << c0.max_size();   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
4

array::operator[]

Accesses an element at a specified position.

 
reference operator[](size_type off);

constexpr const_reference operator[](size_type off) const;

Parameters

off
Position of element to access.

Remarks

The member functions return a reference to the element of the controlled sequence at position off. If that position is invalid, the behavior is undefined.

Example

// std_tr1__array__array_operator_sub.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display odd elements " 1 3"   
    std::cout << " " << c0[1];   
    std::cout << " " << c0[3];   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
1 3

array::operator=

Replaces the controlled sequence.

array <Value>%  operator=(array <Value>% right);

Parameters

right
Container to copy.

Remarks

The member operator assigns each element of right to the corresponding element of the controlled sequence, then returns *this. You use it to replace the controlled sequence with a copy of the controlled sequence in right.

Example

// std_tr1__array__array_operator_as.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    Myarray c1;   
    c1 = c0;   
  
// display copied contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c1.begin();   
        it != c1.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0 1 2 3

array::pointer

The type of a pointer to an element.

typedef Ty *pointer;

Remarks

The type describes an object that can serve as a pointer to elements of the sequence.

Example

// std_tr1__array__array_pointer.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::pointer ptr = &*c0.begin();   
    std::cout << " " << *ptr;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::rbegin

Designates the beginning of the reversed controlled sequence.

reverse_iterator rbegin()noexcept;  
const_reverse_iterator rbegin() const noexcept;

Remarks

The member functions return a reverse iterator that points just beyond the end of the controlled sequence. Hence, it designates the beginning of the reverse sequence.

Example

// std_tr1__array__array_rbegin.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display last element " 3"   
    Myarray::const_reverse_iterator it2 = c0.rbegin();   
    std::cout << " " << *it2;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
3

array::reference

The type of a reference to an element.

typedef Ty& reference;

Remarks

The type describes an object that can serve as a reference to an element of the controlled sequence.

Example

// std_tr1__array__array_reference.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::reference ref = *c0.begin();   
    std::cout << " " << ref;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::rend

Designates the end of the reversed controlled sequence.

reverse_iterator rend()noexcept;  
const_reverse_iterator rend() const noexcept;

Remarks

The member functions return a reverse iterator that points at the first element of the sequence (or just beyond the end of an empty sequence)). Hence, it designates the end of the reverse sequence.

Example

// std_tr1__array__array_rend.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display first element " 0"   
    Myarray::const_reverse_iterator it2 = c0.rend();   
    std::cout << " " << *--it2;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0

array::reverse_iterator

The type of a reverse iterator for the controlled sequence.

typedef std::reverse_iterator<iterator> reverse_iterator;

Remarks

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

Example

// std_tr1__array__array_reverse_iterator.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display last element " 3"   
    Myarray::reverse_iterator it2 = c0.rbegin();   
    std::cout << " " << *it2;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
3

array::size

Counts the number of elements.

constexpr size_type size() const;

Remarks

The member function returns N.

Example

// std_tr1__array__array_size.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display size " 4"   
    std::cout << " " << c0.size();   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
4

array::size_type

The type of an unsigned distance between two element.

typedef std::size_t size_type;

Remarks

The unsigned integer type describes an object that can represent the length of any controlled sequence. It is a synonym for the type std::size_t.

Example

// std__array__array_size_type.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display distance last-first " 4"   
    Myarray::size_type diff = c0.end() - c0.begin();   
    std::cout << " " << diff;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
4

array::swap

Swaps the contents of two arrays.

void swap(array& right);

Parameters

right
Array to swap contents with.

Remarks

The member function swaps the controlled sequences between *this and right. It performs a number of element assignments and constructor calls proportional to N.

Example

// std_tr1__array__array_swap.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    Myarray c1 = {4, 5, 6, 7};   
    c0.swap(c1);   
  
// display swapped contents " 4 5 6 7"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    swap(c0, c1);   
  
// display swapped contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
4 5 6 7  
0 1 2 3

array::value_type

The type of an element.

typedef Ty value_type;

Remarks

The type is a synonym for the template parameter Ty.

Example

// std_tr1__array__array_value_type.cpp   
// compile with: /EHsc   
#include <array>   
#include <iostream>   
  
typedef std::array<int, 4> Myarray;   
int main()   
    {   
    Myarray c0 = {0, 1, 2, 3};   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        std::cout << " " << *it;   
    std::cout << std::endl;   
  
// display contents " 0 1 2 3"   
    for (Myarray::const_iterator it = c0.begin();   
        it != c0.end(); ++it)   
        {   
        Myarray::value_type val = *it;   
        std::cout << " " << val;   
        }   
    std::cout << std::endl;   
  
    return (0);   
    }

0 1 2 3  
0 1 2 3

Condividi tramite

array Class (STL)

Syntax

Parameters

Members

Remarks

Requirements

array::array

Parameters

Remarks

Example

array::assign

Parameters

Remarks

Example

array::at

Parameters

Remarks

Example

array::back

Remarks

Example

array::begin

Remarks

Example

array::cbegin

Return Value

Remarks

array::cend

Return Value

Remarks

array::const_iterator

Remarks

Example

array::const_pointer

Remarks

Example

array::const_reference

Remarks

Example

array::const_reverse_iterator

Remarks

Example

array::crbegin

Return Value

Remarks

Example

array::crend

Return Value

Remarks

Example

array::data

Remarks

Example

array::difference_type

Remarks

Example

array::empty

Remarks

Example

array::end

Remarks

Example

array::fill

Parameters

Remarks

Example

array::front

Remarks

Example

array::iterator

Remarks

Example

array::max_size

Remarks

Example

array::operator[]

Parameters

Remarks

Example