#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; 
s3=s2-s1; 
s3.disp(); 
s3=s2+s1; 
s3.disp(); 
}