C++友元访问私有 指针

Question

#include<iostream>
using namespace std;

class Student{
    public:
        Student(int n,double s):num(n),score(s){}
        friend void max(Student&);
    private:int num;double score;
};
int main(){
    Student stu[5]={Student(101,78.5),Student(111,88.5),
    Student(131,68.5),Student(151,58.5),Student(121,98.5)};
void max(Student &*);
Student *p=&stu[0];
max(p);
return 0;
}

void max(Student &*b)
{
    double max_s=b[0].score;
    int k=0,i;
    for(i=0;i<5;i++)
        if(b[i].score>max_s) {k=i;max_s=b[i].score;}
        cout<<b[k].num <<" "<<max_s<<endl;
}

1.

Answer 1

max函数的参数统一用指针：

#include<iostream>
using namespace std;
class Student{
    public:
        Student(int n,double s):num(n),score(s){}
        friend void max(Student*);
    private:int num;double score;
};
int main(){
    Student stu[5]={Student(101,78.5),Student(111,88.5),
    Student(131,68.5),Student(151,58.5),Student(121,98.5)};
Student *p=&stu[0];
max(p);
return 0;
}
void max(Student *b)
{
    double max_s=b[0].score;
    int k=0,i;
    for(i=0;i<5;i++)
        if(b[i].score>max_s) {k=i;max_s=b[i].score;}
        cout<<b[k].num <<" "<<max_s<<endl;
}