Condividi tramite


hash_map::rend

Returns an iterator that addresses the location succeeding the last element in a reversed hash_map.

const_reverse_iterator rend( ) const; 
reverse_iterator rend( );

Return Value

A reverse bidirectional iterator that addresses the location succeeding the last element in a reversed hash_map (the location that had preceded the first element in the unreversed hash_map).

Remarks

rend is used with a reversed hash_map just as end is used with a hash_map.

If the return value of rend is assigned to a const_reverse_iterator, then the hash_map object cannot be modified. If the return value of rend is assigned to a reverse_iterator, then the hash_map object can be modified.

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

The value returned by rend should not be dereferenced.

In Visual C++ .NET 2003, members of the <hash_map> and <hash_set> header files are no longer in the std namespace, but rather have been moved into the stdext namespace. See The stdext Namespace for more information.

Example

// hash_map_rend.cpp
// compile with: /EHsc
#define _DEFINE_DEPRECATED_HASH_CLASSES 0
#include <hash_map>
#include <iostream>

int main( )
{
   using namespace std;
   using namespace stdext;
   hash_map <int, int> hm1;

   hash_map <int, int> :: iterator hm1_Iter;
   hash_map <int, int> :: reverse_iterator hm1_rIter;
   hash_map <int, int> :: const_reverse_iterator hm1_crIter;
   typedef pair <int, int> Int_Pair;

   hm1.insert ( Int_Pair ( 1, 10 ) );
   hm1.insert ( Int_Pair ( 2, 20 ) );
   hm1.insert ( Int_Pair ( 3, 30 ) );

   hm1_rIter = hm1.rend( );
   hm1_rIter--;
   cout << "The last element of the reversed hash_map hm1 is "
        << hm1_rIter -> first << "." << endl;

   // begin can be used to start an iteration 
   // through a hash_map in a forward order
   cout << "The hash_map is: ";
   for ( hm1_Iter = hm1.begin( ) ; hm1_Iter != hm1.end( );
   hm1_Iter++)
      cout << hm1_Iter -> first << " ";
      cout << "." << endl;

   // rbegin can be used to start an iteration 
   // through a hash_map in a reverse order
   cout << "The reversed hash_map is: ";
   for ( hm1_rIter = hm1.rbegin( ) ; hm1_rIter != hm1.rend( );
      hm1_rIter++)
      cout << hm1_rIter -> first << " ";
      cout << "." << endl;

   // A hash_map element can be erased by dereferencing to its key 
   hm1_rIter = --hm1.rend( );
   hm1.erase ( hm1_rIter -> first );

   hm1_rIter = hm1.rend( );
   hm1_rIter--;
   cout << "After the erasure, the last element "
        << "in the reversed hash_map is "
        << hm1_rIter -> first << "." << endl;
}

The last element of the reversed hash_map hm1 is 1.
The hash_map is: 1 2 3 .
The reversed hash_map is: 3 2 1 .
After the erasure, the last element in the reversed hash_map is 2.

Requirements

Header: <hash_map>

Namespace: stdext

See Also

Concepts

hash_map Class

hash_map Members

Standard Template Library