全局函数做友元

#include <iostream>

class Person
{
   //print是Person朋友 可以访问类中私有内容
   friend void print(Person &person);

public:
    Person(int age):
        age(age),
        sex(0)
    {
    }

public:
   int age;
private:
   int sex;
};

void print(Person &person)
{
   std::cout << person.age << std::endl;
   std::cout << person.sex << std::endl;
}

int main()
{
   Person p(10);
   print(p);

   return 0;
}