一次C++作业

#include<iostream>
using namespace std;

//1.  定义人民币类RMB，包含：
//私有数据成员    int yuan（元）、int jiao（角）、int fen（分）、bool mark（标志，表示正、负数）
//成员函数            用（元，角，分，标志）构造RMB对象
//用double数据构造RMB对象
//类型转换，把RMB对象转换为double值
//友元函数            重载 << ，以“元角分”形式输出RMB对象值
//重载 >> ，以“元角分”形式输入RMB对象值

//此处定义class RMB
class RMB
{
	friend istream &operator >> (istream& input, RMB& r);
	friend ostream& operator<<(ostream& output, const RMB &r);
public:
	RMB(){}
	RMB(double money)
	{
		if (money < 0)
		{
			mark = 1;
			money = -money;
		}
		yuan = int(money);
		money = (money - int(money)) * 10;
		jiao = int(money);
		money = (money - int(money)) * 10;
		fen = int(money);
	}

	operator double()
	{
		double money =  yuan + jiao*0.1 + fen*0.01;
		return mark == 1 ? -money : money;
	}
	
private:
	int yuan;
	int jiao;
	int fen;
	bool mark = 0;
};

istream &operator >> (istream& input, RMB& r)
{
	input >> r.yuan >> r.jiao >> r.fen;
	return input;
}

ostream& operator<<(ostream& output, const RMB &r)
{
	if (r.mark == 1)
		output << '-';
	output << r.yuan << "元" << r.jiao << "角" << r.fen << "分";

	return output;
}
int main()
{
	RMB a, b;
	double c;
	cout << "a :\n";  cin >> a;
	cout << "b :\n";  cin >> b;
	cout << "c :\n";  cin >> c;
	cout << "a = " << a << "\tb = " << b << "\tc = " << RMB(c) << endl;
	cout << "a + c = " << RMB(a + c) << endl;
	cout << "a - b = " << RMB(a - b) << endl;
	cout << "b * 2 = " << RMB(b * 2) << endl;
	cout << "a * 0.5 = " << RMB(a*0.5) << endl;
}