9-1.cpp

为初学者提供的最佳的C++程序设计源程序库

#include<iostream.h>
class Sample
{
  int n;
public:
	Sample(){}
	Sample(int i){n=i;}
	friend Sample operator-(Sample &,Sample &);
	friend Sample operator+(Sample &,Sample &);
	void disp() {cout<<"n="<<n<<endl;}
};
Sample operator-(Sample &s1,Sample &s2)
{
  int m=s1.n-s2.n;
  return Sample(m);
}
Sample operator + (Sample &s1,Sample &s2)
{
  int m=s1.n+s2.n;
  return Sample(m);
}
void main()
{
  Sample s1(10),s2(20),s3,s4;
  s3=s2-s1;
  s4.disp();
  s3=s1+s2;
  s4.disp();
}