hash_multiset::difference_type

A signed integer type that provides the difference between two iterators that address elements within the same hash_multiset.

typedef list<typename _Traits::value_type, typename _Traits::allocator_type>::difference_type difference_type;

Remarks

The difference_type is the type returned when subtracting or incrementing through iterators of the container. The difference_type is typically used to represent the number of elements in the range [_First, _Last) between the iterators _First and _Last, includes the element pointed to by _First and the range of elements up to, but not including, the element pointed to by _Last.

Note that although difference_type is available for all iterators that satisfy the requirements of an input iterator, which includes the class of bidirectional iterators supported by reversible containers such as set. Subtraction between iterators is only supported by random-access iterators provided by a random-access container such as vector or deque.

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

int main( )
{
   using namespace std;
   using namespace stdext;

   hash_multiset <int> hms1;
   hash_multiset <int>::iterator hms1_Iter, hms1_bIter, hms1_eIter;

   hms1.insert( 20 );
   hms1.insert( 10 );

   // hash_multiset elements need not be unique
   hms1.insert( 20 );

   hms1_bIter = hms1.begin( );
   hms1_eIter = hms1.end( );

   hash_multiset <int>::difference_type   df_typ5, df_typ10,
        df_typ20;

   df_typ5 = count( hms1_bIter, hms1_eIter, 5 );
   df_typ10 = count( hms1_bIter, hms1_eIter, 10 );
   df_typ20 = count( hms1_bIter, hms1_eIter, 20 );

   // The keys & hence the elements of a hash_multiset
   // need not be unique and may occur multiple times
   cout << "The number '5' occurs " << df_typ5
        << " times in hash_multiset hms1.\n";
   cout << "The number '10' occurs " << df_typ10
        << " times in hash_multiset hms1.\n";
   cout << "The number '20' occurs " << df_typ20
        << " times in hash_multiset hms1.\n";

   // Count the number of elements in a hash_multiset
   hash_multiset <int>::difference_type  df_count = 0;
   hms1_Iter = hms1.begin( );
   while ( hms1_Iter != hms1_eIter)
   {
      df_count++;
      hms1_Iter++;
   }

   cout << "The number of elements in the hash_multiset hms1 is " 
        << df_count << "." << endl;
}

The number '5' occurs 0 times in hash_multiset hms1.
The number '10' occurs 1 times in hash_multiset hms1.
The number '20' occurs 2 times in hash_multiset hms1.
The number of elements in the hash_multiset hms1 is 3.

Requirements

Header: <hash_set>

Namespace: stdext

See Also

Reference

hash_multiset Class

Standard Template Library