C++类属算法count

// Illustrating the generic count algorithm
#include < iostream >
#include < cassert >
#include < algorithm >
#include < functional >
using namespace std;

int main()
{
cout << " Illustrating the generic count algorithm. " << endl;
int a[] = { 0 , 0 , 0 , 1 , 1 , 1 , 2 , 2 , 2 };

// Count the number of values in the array a
// that are equal to 1:
int final_count = count( & a[ 0 ], & a[ 9 ], 1 );

assert (final_count == 3 );

// Determine the number of array elements that are not
// equal to 1:
final_count = count_if( & a[ 0 ], & a[ 9 ],
bind2nd(not_equal_to < int > (), 1 ));

// There are 6 elements not equal to 1.
assert (final_count == 6 );
cout << " --- Ok. " << endl;
return 0 ;
}