题解 | 友元全局函数

#include <iostream>
using namespace std;

class Person {
    // write your code here......
   friend void showAge(Person& p);

    public:
        Person(int age) {
            this->age = age;
        }

    private:
        int age;
};

void showAge(Person& p) {
    cout << p.age << endl;
}

int main() {

    Person p(10);
    showAge(p);

    return 0;
}