e3.cpp

一、教学目的： 能理解C++中运算符重载的需要性

#include<iostream.h>          

class RMB
{
public:
	RMB(unsigned int d,unsigned int c);
	friend RMB operator +(RMB&,RMB&);
	friend RMB& operator ++(RMB&);
	void display()
	{
		cout<<(yuan+jf/100.0)<<endl;
	}
protected:
	unsigned int yuan;//元
	unsigned int jf;//角分
};
RMB::RMB(unsigned int d,unsigned int c)
{
	yuan=d;
	jf=c;
	while(jf>=100)
	{                  //以使构造时，确保角分值小于100
		yuan++;
		jf-=100;
	}
}
RMB operator+(RMB& s1,RMB& s2)
{
	unsigned int jf=s1.jf+s2.jf;
	unsigned int yuan=s1.yuan+s2.yuan;
	RMB result(yuan,jf);
	return result;
}
RMB& operator ++(RMB& s)
{
	s.jf++;
	if(s.jf>=100)
	{
		s.jf-=100;
		s.yuan++;
	}
	return s;
}
void main()
{
	RMB d1(1,60);
	RMB d2(2,50);
	RMB d3(0,0);
	d3=d1+d2;
	++d3;
	d3.display();
}