multiset::count

Returns the number of elements in a multiset whose key matches a parameter-specified key.

size_type count( 
   const Key& _Key 
) const;

Parameters

  • _Key
    The key of the elements to be matched from the multiset.

Return Value

The number of elements in the multiset whose sort key matches the parameter key.

Remarks

The member function returns the number of elements x in the range

[lower_bound (_Key ), upper_bound (_Key ) ).

Example

When compiling this example with the /Wp64 flag or on a 64-bit platform, compiler warning C4267 will be generated. For more information on this warning, see Compiler Warning (level 3) C4267.

// multiset_count.cpp
// compile with: /EHsc
#include <set>
#include <iostream>

int main()
{
    using namespace std;
    multiset<int> ms1;
    multiset<int>::size_type i;

    ms1.insert(1);
    ms1.insert(1);
    ms1.insert(2);

    // Elements do not need to be unique in multiset,
    // so duplicates are allowed and counted.
    i = ms1.count(1);
    cout << "The number of elements in ms1 with a sort key of 1 is: "
         << i << "." << endl;

    i = ms1.count(2);
    cout << "The number of elements in ms1 with a sort key of 2 is: "
         << i << "." << endl;

    i = ms1.count(3);
    cout << "The number of elements in ms1 with a sort key of 3 is: "
         << i << "." << endl;
}
The number of elements in ms1 with a sort key of 1 is: 2.
The number of elements in ms1 with a sort key of 2 is: 1.
The number of elements in ms1 with a sort key of 3 is: 0.

Requirements

Header: <set>

Namespace: std

See Also

Reference

multiset Class

Standard Template Library