第9周任务3（实现分数类中<<和>>运算符的重载）

/* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2011, 烟台大学计算机学院学生
* All rights reserved.
* 文件名称：
* 作    者：   臧鹏
* 完成日期：   2012   年  4 月 16 日
* 版 本 号：

* 对任务及求解方法的描述部分
* 输入描述：
* 问题描述：实现分数类中的<<和>>运算符重载，实现分数的输入和输出
* 程序头部的注释结束
*/
#include<iostream>
using namespace std;

int gcd(int x,int y) ;//声明为普通函数

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

CFraction operator+(CFraction &t);

CFraction operator-(CFraction &t);

CFraction operator*(CFraction &t);

CFraction operator/(CFraction &t);

friend CFraction operator-(CFraction &t);//取反

bool operator>(CFraction &t);

bool operator<(CFraction &t);

bool operator>=(CFraction &t);

bool operator<=(CFraction &t);

bool operator==(CFraction &t);

bool operator!=(CFraction &t);

void Simplify(int n);            //化简（使分子分母没有公因子）

friend istream & operator >>(istream &in,CFraction &t);

friend ostream & operator <<(ostream &out,CFraction &t);

};

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

}

void CFraction::Set(int nu,int de) //置值，改变值时用
{
if(de !=0)
{
nume = nu;
deno = de;
}
else
{
cout<<"分母不能为零"<<endl;
exit(0);
}

nume = nu;

deno = de;

}

void CFraction::Simplify(int n)        //化简（使分子分母没有公因子）
{
n = gcd(nume,deno);

nume = nume/n;
deno = deno/n;

}

int gcd(int x,int y)  //求公约数的函数
{
int r;
while( y!= 0)
{
r = x%y;
x = y;
y = r;
}
return x;
}

CFraction CFraction:: operator+(CFraction &t)
{
CFraction cf;
if(deno==t.deno)  //分母相同时比较分子
{
cf.deno=deno;
cf.nume=nume+t.nume;
}
else  //否则同分比较分子
{
cf.deno=deno*t.deno;
cf.nume=nume*t.deno+deno*t.nume;
}
return cf;
}

CFraction CFraction:: operator-(CFraction &t)
{
CFraction cf;
if(deno==t.deno)
{
cf.deno=deno;
cf.nume=nume-t.nume;
}
else
{
cf.deno=deno*t.deno;
cf.nume=t.deno*nume-t.nume*deno;
}
return cf;
}

CFraction  CFraction:: operator*(CFraction &t)
{
CFraction cf;
cf.deno = deno*t.deno;
cf.nume = nume*t.nume;
return cf;
}

CFraction  CFraction:: operator/(CFraction &t)
{
CFraction cf;
cf.deno = deno*t.nume;
cf.nume = nume*t.deno;
return cf;
}

CFraction operator-(CFraction &t)//取反
{
CFraction cf;
cf.deno  = -t.deno;
cf.nume  = t.nume;
return(cf);
}

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

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

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

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

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

bool CFraction::operator!=(CFraction &t)
{
if(!operator==(t))
return true;
else
return false;
}

istream & operator >>(istream &in,CFraction &t)
{
char a;
while(1)
{
cout<<"请输入分数(形式 x/x)："<<endl;
cin>>t.nume>>a>>t.deno;
if(a != '/'||t.deno ==0)//注意符号不对和分母为0的情况
{
cout<<"格式不正确，请重新输入："<<endl;
continue;
}
else break;
}
return cin;
}

ostream & operator <<(ostream &out,CFraction &t)//在输出时进行化简
{

if(t.nume ==0)
{
cout<<"0"<<endl;
}
else
{
int m = gcd(t.nume,t.deno);
cout<<(t.nume/m)<<'/'<<(t.deno/m)<<endl;

}
return out;
}

int main ()
{
CFraction cf1,cf2,cf3;

cin>>cf1;
cout<<"cf1 = "<<cf1;

cin>>cf2;
cout<<"cf2 = "<<cf2;

cout<<"cf1*cf2= "<<cf1*cf2;

cout<<"cf1-cf2= "<<cf1-cf2;

cout<<"cf1+cf2= "<<cf1+cf2;

cout<<"cf1/cf2= "<<cf1/cf2;

cout<<"-cf1 = "<<-cf1;

if (cf1>cf2) cout<<"cf1>cf2"<<endl;

if (cf1<cf2) cout<<"cf1<cf2"<<endl;

if (cf1==cf2) cout<<"cf1＝cf2"<<endl;

if (cf1!=cf2) cout<<"cf1≠cf2"<<endl;

if (cf1>=cf2) cout<<"cf1≥cf2"<<endl;

if (cf1<=cf2) cout<<"cf1≤cf2"<<endl;

system("pause");

return 0;

}