源代码如下：
#include<iostream>
using namespace std;
class score; // 如果我注释掉此语句，编译器会报错，但是是乱报错的
class student
{
private:
int name;
public:
student(int na) //构造函数
{
name = na;
}
void view(const score &A);
};
class score
{
private:
int stu, sco, teach;
public:
friend void init(int x, int y, int z, score &B)
{
B.stu = x;
B.sco = y;
B.teach = z;
}
friend void student::view(const score &A);//另一个类的对象作为这个类的成员函数
};
void student::view(const score &A)
{
if(name == A.stu)
{
cout<<"***查询成绩***"<<endl;
cout<<"学号："<<name<<endl;
cout<<"成绩："<<A.sco<<endl;
cout<<"打分老师编号："<<A.teach<<endl;
}
}
void main()
{
int x, y, na, te;
score BB;
cout<<"教师登陆"<<endl;
cout<<"输入学生号，成绩，教师编号："<<endl;
cin>>x>>y>>te;
init(x,y,te,BB);
cout<<" 学生登陆 "<<endl;
cin>>na;
student AA(na);
AA.view(BB);
}
我注释掉
//class score;
编译器报错如下：
Compiling...
8-3-4.cpp
E:\vc++自编\8-3-4.cpp(16) : error C2143: syntax error : missing ',' before '&'
E:\vc++自编\8-3-4.cpp(16) : error C2059: syntax error : '&'
E:\vc++自编\8-3-4.cpp(31) : error C2245: nonexistent function 'student::view' specified as friend
E:\vc++自编\8-3-4.cpp(35) : error C2511: 'view' : overloaded member function 'void (const class score &)' not found in 'student'
E:\vc++自编\8-3-4.cpp(7) : see declaration of 'student'
E:\vc++自编\8-3-4.cpp(56) : error C2664: 'view' : cannot convert parameter 1 from 'class score' to 'const int'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
执行 cl.exe 时出错.
8-3-4.obj - 1 error(s), 0 warning(s)
报错结果 信不信由你 哈哈............信了你就完了 ——有的你折腾！！！！
