C++ Tutorial/vector/vector count

#include <iostream>
using std::cout;
using std::endl;
#include <algorithm>
#include <numeric>
#include <vector>
#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;
}