set::count (STL Samples)

Illustrates how to use the set::count Standard Template Library (STL) function in Visual C++.

template<class _K, class _Pr, class _A> 
   class set 
   { 
      public: 
      // Function 1: 
      size_type count(const _K& _Kv) const; 
   }

Remarks

The count function is used to determine the number of elements in the controlled sequence that have a particular key.

Example

// SetCount.cpp
// compile with: /EHsc
//
//      Illustrates how to use the count function to determine how
//      many elements have a particular key.
//
// Functions:
//    count        Returns the number of elements in the controlled
//                 sequence that have a particular key.
//////////////////////////////////////////////////////////////////////

#pragma warning(disable:4786)
#include <set>
#include <iostream>

using namespace std ;

typedef set<int> SET_INT;

void truefalse(int x)
{
  cout << (x?"True":"False") << endl;
}

int main() {
  SET_INT s1;
  SET_INT::_Pairib pib;
  cout << "s1.insert(5)" << endl;
  pib=s1.insert(5);
  cout << "Inserted element: ";
  truefalse(pib.second);  // True

  cout << "s1.insert(5)" << endl;
  pib=s1.insert(5);
  cout << "Inserted element: ";
  truefalse(pib.second);  // True

  cout << "s1.insert(8)" << endl;
  s1.insert(8);

  cout << "s1.insert(12)" << endl;
  s1.insert(12);

  cout << "s1.count(5) returned ";
  cout << s1.count(5) << endl;    // 1

  cout << "s1.count(9) returned ";
  cout << s1.count(9) << endl;    // 0
}

Output

s1.insert(5)
Inserted element: True
s1.insert(5)
Inserted element: False
s1.insert(8)
s1.insert(12)
s1.count(5) returned 1
s1.count(9) returned 0

Requirements

Header: <set>

See Also

Concepts

Standard Template Library Samples