hash_set::rbegin

Returns an iterator addressing the first element in a reversed hash_set.

Syntax

      const_reverse_iterator rbegin( ) const; 
reverse_iterator rbegin( );

Return Value

A reverse bidirectional iterator addressing the first element in a reversed hash_set or addressing what had been the last element in the unreversed hash_set.

Remarks

rbegin is used with a reversed hash_set just as begin is used with a hash_set.

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

rbegin can be used to iterate through a hash_set backwards.

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_set_rbegin.cpp
// compile with: /EHsc
#include <hash_set>
#include <iostream>

int main( )
{
   using namespace std;
   using namespace stdext;
   hash_set <int> hs1;
   hash_set <int>::iterator hs1_Iter;
   hash_set <int>::reverse_iterator hs1_rIter;

   hs1.insert( 10 );
   hs1.insert( 20 );
   hs1.insert( 30 );

   hs1_rIter = hs1.rbegin( );
   cout << "The first element in the reversed hash_set is "
        << *hs1_rIter << "." << endl;

   // begin can be used to start an iteration 
   // throught a hash_set in a forward order
   cout << "The hash_set is: ";
   for ( hs1_Iter = hs1.begin( ) ; hs1_Iter != hs1.end( );
         hs1_Iter++ )
      cout << *hs1_Iter << " ";
   cout << endl;

   // rbegin can be used to start an iteration 
   // throught a hash_set in a reverse order
   cout << "The reversed hash_set is: ";
   for ( hs1_rIter = hs1.rbegin( ) ; hs1_rIter != hs1.rend( );
         hs1_rIter++ )
      cout << *hs1_rIter << " ";
   cout << endl;

   // A hash_set element can be erased by dereferencing to its key 
   hs1_rIter = hs1.rbegin( );
   hs1.erase ( *hs1_rIter );

   hs1_rIter = hs1.rbegin( );
   cout << "After the erasure, the first element "
        << "in the reversed hash_set is "<< *hs1_rIter << "."
        << endl;
}

The first element in the reversed hash_set is 30.
The hash_set is: 10 20 30 
The reversed hash_set is: 30 20 10 
After the erasure, the first element in the reversed hash_set is 20.

Requirements

Header: <hash_set>

Namespace: stdext

See Also

hash_set Class
Standard Template Library