2. 全局函数作友元

在类内的公有权限区域使用friend关键字声明 友元函数
在类外进行友元函数的定义

#include <iostream>
#include <string>
using namespace std;
class Student{
    public:
        friend void getData(Student &student);  // 在公有权限区域声明友元函数
        string school = "CTGU";
        Student(){
            name = "yxr";
            age = 18;
        }
        ~Student(){
            cout << "析构函数的调用" << endl;
        }
    private:
        string name;
        int age;
};
void getData(Student &student){
    cout << student.school << endl;
    cout << student.name << endl;
    cout << student.age << endl;
}
int main(){
    Student student;
    getData(student);
    system("pause");
    return 0;
}