#include <iostream.h> class Birthday { private: int day; int month; int year; public: Birthday(int y,int z, int k) { day = y; month = z; year = k;} ~Birthday(){}

friend changeday(Birthday t1);

int GetY(){ return day;} int GetZ(){ return month;} int GetK(){ return year;} }; changeday(Birthday t1) { t1.day = 15; t1.month = 1; t1.year = 1984; }

void main() { Birthday t2; changeday(t2); cout << t2.GetK()<< t2.GetZ() << t2.GetY() << endl; } 给我看看哪能时错了呀？？？？？？？？？？？？？？？

#include<iostream> using namespace std;//standard c class Birthday { private: int day; int month; int year; public: Birthday(){} Birthday(int y,int z, int k) { day = y; month = z; year = k;} ~Birthday(){}

friend void changeday(Birthday t1);

int GetY(){ return day;} int GetZ(){ return month;} int GetK(){ return year;} }; void changeday(Birthday t1) { t1.day = 15; t1.month = 1; t1.year = 1984; }

int main() { Birthday t2; changeday(t2); cout << t2.GetK()<< t2.GetZ() << t2.GetY() << endl; system("pause");//make screen stop } 友元函数是没错，但是你缺醒构造了t2却没有声明缺醒构造函数所以报错了 还有，要注意一些细节 最好向标准的c靠拢

你这个程序应该这样

#include <iostream.h> class Birthday { private: int day; int month; int year; public: Birthday(int y=0,int z=0, int k=0) { day = y; month = z; year = k;} ~Birthday(){}

friend Birthday changeday(Birthday t1);

int GetY(){ return day;} int GetZ(){ return month;} int GetK(){ return year;} }; Birthday changeday(Birthday t1) { t1.day = 15; t1.month = 1; t1.year = 1984; return t1;}

void main() { Birthday t2; changeday(t2); cout << t2.GetK()<< t2.GetZ() << t2.GetY() << endl; }

这样基本就正确啦

#include <iostream>
using namespace std;
class Birthday
{
private:
int day;
int month;
int year;
public:
Birthday(int y,int z, int k)
{ day = y; month = z; year = k;}
~Birthday(){}

friend void changeday(Birthday t1);

int GetY(){ return day;}
int GetZ(){ return month;}
int GetK(){ return year;}
};
void changeday(Birthday t1)
{
t1.day = 15;
t1.month = 1;
t1.year = 1984;
cout << t1.GetK()<< t1.GetZ() << t1.GetY() << endl;
}

int main()
{
Birthday t2(19,9,1982);
cout<<"Before change......"<<endl;
cout << t2.GetK()<< t2.GetZ() << t2.GetY() << endl;
cout<<"After change......"<<endl;
changeday(t2);

system("pause");
return 0;
}

另外在下也是一菜鸟，不知道你的意思是不是这个～～～～

太谢谢你了，给我解决了这个问题。