#include <iostream>
#include <string>

class student;

template <typename T, class fun>
int my_count_if(T *a,int n,fun f) //f 是判断特征的函数
{
    int count = 0;
    for ( int i=0; i<n; ++i    )
    {
        if (a[i].f)
        {
            count ++;
        }
    }
    return count ;
}




class student
{
private:
    int score;
    std::string  name;
public:
    student(int a=0,char* s="")
        :score(a),name(s){}

    student (const student& s)
    {
        if (this!=&s)
        {
            this->name=s.name;
            this->score=s.score;
        }
    }

    student &operator=(const student&rhs)
    {
        if (this!=&rhs)
        {
        this->name=rhs.name;
        this->score=rhs.score;
        }
        return *this;
    }

    bool bujige()    //定义不及格的函数
    {
        return score<60;
    }

  
};

int main()
{
    student a[]={student(50,"tom"),student(49,"jerry"),student(91,"henry")};
    int n=sizeof(a)/sizeof(*a);
    int num=my_count_if(a,n,student::bujige);
}

//其中bujige是作为一个判定性质的函数

谢谢啊

恩恩