C++ count和count_if

#include <iostream>#include <algorithm>#include <array>#include <vector>#include <functional>using namespace std;bool f(int i){return i<15;}int main(){array<int,8> test = {3,5,7,11,13,17,19,23};int t;t=count(test.begin(),test.end(),5);t=count_if(test.begin(),test.end(),f);//统计小于15的元素个数t=count_if(test.begin(),test.end(),bind2nd(less<int>(),15));//利用函数模版cout<<t;return 0;}