C++/Vector/vector count

Count elements in a vector by value

<source lang="cpp">

1. include <iostream>

using std::cout; using std::endl;

1. include <algorithm>
2. include <numeric>
3. include <vector>
4. include <iterator>

int main() {

  std::ostream_iterator< int > output( cout, " " );
  int a2[ 10 ] = { 100, 2, 8, 1, 50, 3, 8, 8, 9, 10 };
  std::vector< int > v2( a2, a2 + 10 ); // copy of a2
  cout << "Vector v2 contains: ";
  std::copy( v2.begin(), v2.end(), output );
  // count number of elements in v2 with value 8
  int result = std::count( v2.begin(), v2.end(), 8 );
  cout << "\nNumber of elements matching 8: " << result;
  cout << endl;
  return 0;

} /* Vector v2 contains: 100 2 8 1 50 3 8 8 9 10 Number of elements matching 8: 3

*/        
 </source>