C++友元friend

                                 C++友元类                                   

    刚学C++，被友元类搞的不行！有天同事问题，我自己都不知道说了些什么。于是在此总结下。

    貌似谭老曾说过：“private标识为私有,就好像家中的卧室，一般人是不可看我们的卧室的!但朋友例外”

    所以，我们可已把可以访问我们卧室的人定义为朋友角色。也就是说，可以把可以访问我们的private变量的函数或者类申明为我们的友元类。

    EX1：友元函数class CStudent{public:protected:private:int m_nYuWen;int m_nShuXue;//int nTotal;friend int Compute();};int main(int argc, char* argv[]){printf("The student's score is %d!/n", Compute());return 0;}int Compute(){CStudent stu;stu.m_nYuWen = 100;stu.m_nShuXue = 100;int nTotal;nTotal = stu.m_nYuWen + stu.m_nShuXue;return nTotal;}

 

 

    EX2：友元类

                       class CStudent{private:friend class CTeacher;public:protected:private:int m_nYuWen;int m_nShuXue;};class CTeacher{public:int Compute();protected:private:};int CTeacher::Compute(){CStudent stu;stu.m_nYuWen = 100;stu.m_nShuXue = 100;int nTotal;nTotal = stu.m_nYuWen + stu.m_nShuXue;return nTotal;}int main(int argc, char* argv[]){CTeacher teacher;printf("The student's score is %d!/n", teacher.Compute());return 0;}