C++对象的++,--运算符重载 374-39

#include <iostream.h>

class CPoint
{
public:
 CPoint(int i=0,int j=0)
 {
  x=i;
  y=j;
 }

 CPoint operator++();
 CPoint operator++(int);
 CPoint operator--();
 CPoint operator--(int);

 void print()
 {
  cout<<"x="<<x<<" y="<<y<<endl;
 }

private:
 int x,y;
};

CPoint CPoint::operator++()
{
 x++;
 y++;
 return *this;
}

CPoint CPoint::operator ++(int)
{
 CPoint a;
 a.x =x;
 a.y=y;
 x++;
 y++;
 return a;

}

CPoint CPoint::operator--()
{
 x--;
 y--;
 return *this;
}

CPoint CPoint::operator --(int)
{
 CPoint a;
 a.x=x;
 a.y=y;
 x--;
 y--;
 return a;
}

void main()
{
 CPoint a;
 CPoint b;
 
 cout<<"CPoint a; /na.print() ";
 a.print();
 cout<<endl;

 b=a++;
 cout<<"CPoint b;"<<endl;
 cout<<"b=a++; b.print() ";
 b.print();
 cout<<"       a.print() ";
 a.print();
 cout<<endl;

 b=++a;
 cout<<"b=++a; b.print() ";
 b.print();
 cout<<"       a.print() ";
 a.print();
 cout<<endl;

 b=a--;
 cout<<"b=a--; b.print() ";
 b.print();
 cout<<"       a.print() ";
 a.print();
 cout<<endl;

 b=--a;
 cout<<"b=--a; b.print() ";
 b.print();
 cout<<"       a.print() ";
 a.print();
}