第九周 项目三：定义分数类中的<<和>>运算符重载

/*
* 程序的版权和版本声明部分
* Copyright (c)2013, 烟台大学计算机学院学生
* All rightsreserved.
* 作    者：   李 洋
* 完成日期： 2013 年 5 月  7 日
* 版本号： v1.0
* 输入描述：
* 问题描述：
* 输出：
*/
#include<iostream>
using namespace std;
int gcd(int m, int n);
class CFraction
{private:
    int nume;  // 分子
    int deno;  // 分母
public:
	CFraction(int nu=0,int de=1);   //构造函数，初始化用
	void set(int nu=0,int de=1);    //置值，改变值时用
	void simplify();
	friend istream&operator>>(istream &,CFraction &);
	friend ostream&operator<<(ostream &,CFraction &);
	CFraction operator+(CFraction &c);
	CFraction operator-(CFraction &c);
	CFraction operator*(CFraction &c);
	CFraction operator/(CFraction &c);
	CFraction operator-();    //求反
	bool operator>(CFraction &c);
	bool operator<(CFraction &c);
	bool operator==(CFraction &c);

};

istream&operator>>(istream &input,CFraction &c)
{
    cout<<"请输入分数（格式：分子、分母）：";
    input>>c.nume>>c.deno;
    return input;
}

ostream&operator<<(ostream &output,CFraction &c)
{
    output<<c.nume<<"/"<<c.deno<<endl;
    return output;
}

CFraction::CFraction(int nu,int de)
{
    nume=nu;
    deno=de;
}

void CFraction::set(int nu,int de)
{
    nume=nu;
    deno=de;
}
void CFraction::simplify()
{
	int m=gcd(nume,deno);
	deno/=m;
	nume/=m;
}

// 求m，n的最大公约数
int gcd(int m, int n)
{
	int min;
	if(m<n)
	{
	    for(min=m;min>0;--min)
	    {
	        if(m%min==0&&n%min==0)
                return min;
	    }
	}
	else
	{
        for(min=n;min>0;--min)
	    {
	        if(m%min==0&&n%min==0)
                return min;
	    }
	}
}

CFraction CFraction::operator+(CFraction &c)
{
    return CFraction(nume*c.deno+deno*c.nume,deno*c.deno);
}

CFraction CFraction::operator-(CFraction &c)
{
    return CFraction(nume*c.deno-deno*c.nume,deno*c.deno);
}

CFraction CFraction::operator*(CFraction &c)
{
    return CFraction(nume*c.nume,deno*c.deno);
}

CFraction CFraction::operator/(CFraction &c)
{
    return CFraction(nume*c.deno,deno*c.nume);
}

CFraction CFraction::operator-()
{
    return CFraction(deno,nume);
}

bool CFraction::operator>(CFraction &c)
{

    if(nume*c.deno>deno*c.nume)
		return true;
    else
		return false;
}

bool CFraction::operator<(CFraction &c)
{
    if(nume*c.deno<deno*c.nume)
		return true;
    else
		return false;
}

bool CFraction::operator==(CFraction &c)
{
    if(nume*c.deno==deno*c.nume)
		return true;
    else
		return false;
}

int main()
{
    CFraction c1,c2,c3;
    cin>>c1;
    cout<<"c1= ";
    cout<<c1;

    cin>>c2;
    cout<<"c2= ";
    cout<<c2;

    c3=c1+c2;
    c3.simplify();
    cout<<"c1+c2= ";
    cout<<c3;

    c3=c1-c2;
    cout<<"c1-c2= ";
    cout<<c3;

    c3=c1*c2;
    c3.simplify();
    cout<<"c1*c2= ";
    cout<<c3;

    c3=c1/c2;
    c3.simplify();
    cout<<"c1/c2= ";
    cout<<c3;

    c3=-c1;
    cout<<"c1求反为：";
    cout<<c3;

    cout<<"下面比较两个分数大小：\n";
	if(c1>c2)
        cout<<"c1>c2"<<endl;
	if(c1<c2)
        cout<<"c1<c2"<<endl;
	if(c1==c2)
        cout<<"c1=c2"<<endl;

	return 0;
}