e-6-1-1.txt

最后声明

#include "stdafx.h"
#include <iostream>

using namespace std;
class R1;
class R2;
class R1{
    int r;
public:
	R1(int i)
	{r=i;}
friend void sq(R1 a,R2 b);
};
class R2{
int r;
public:
R2(int i){
r=i;
}
friend void sq(R1 a,R2 b);
};
void sq(R1 a,R2 b){
  cout<<"The fucking 平方差 is "<<a.r*a.r-b.r*b.r<<endl;
}
void main()
{ R1 c(12);
R2 d(11);
sq(c,d);

system ("pause");
}