C++ Tutorial/set multiset/multiset count

Count elements in multiset by value

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <set> // multiset class-template definition
2. include <algorithm> // copy algorithm
3. include <iterator> // ostream_iterator

int main() {

  int a[ 10 ] = { 7, 22, 9, 1, 18, 30, 100, 22, 85, 13 };
  std::multiset< int, std::less< int > > intMultiset;
  std::ostream_iterator< int > output( cout, " " );
  cout << "There are currently " << intMultiset.count( 15 )
     << " values of 15 in the multiset\n";
  intMultiset.insert( 15 );
  intMultiset.insert( 15 );
  cout << "After inserts, there are " << intMultiset.count( 15 )
     << " values of 15 in the multiset\n\n";

  cout << endl;
  return 0;

}</source>

There are currently 0 values of 15 in the multiset
After inserts, there are 2 values of 15 in the multiset

Count the value in multiset

<source lang="cpp">#include <iostream>

1. include <set>
2. include <algorithm>

using namespace std; int main() {

  const int SIZE = 10;
  int a[ SIZE ] = { 7, 22, 9, 1, 18, 30, 100, 22, 85, 13 };
  typedef multiset< int, less< int > > ims;
  ims intMultiset;    // ims for "integer multiset"
  cout << "There are currently " << intMultiset.count( 15 )
       << " values of 15 in the multiset\n";   
  return 0;

}</source>

multiset.count

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <set> // multiset class-template definition
2. include <algorithm> // copy algorithm
3. include <iterator> // ostream_iterator

int main() {

  int a[ 10 ] = { 7, 22, 9, 1, 18, 30, 100, 22, 85, 13 };
  std::multiset< int, std::less< int > > intMultiset;
  std::ostream_iterator< int > output( cout, " " );
  cout << "There are currently " << intMultiset.count( 15 )
     << " values of 15 in the multiset\n";
  intMultiset.insert( 15 );
  intMultiset.insert( 15 );
  cout << "After inserts, there are " << intMultiset.count( 15 )
     << " values of 15 in the multiset\n\n";

  cout << endl;
  return 0;

}</source>

There are currently 0 values of 15 in the multiset
After inserts, there are 2 values of 15 in the multiset