C++第八周【任务四】分数类中的对象可以和整型数进行四则运算，且运算符合交换律。

/* (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 ：C++第八周【任务四】分数类中的对象可以和整型数进行四则运算，且运算符合交换律。
* 作    者： 李洪悬
* 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：分数类中的对象可以和整型数进行四则运算，且运算符合交换律

* 程序输出：
* 程序头部的注释结束
*/

#include<iostream>

using namespace std;

class CFraction
{
private:
int nume;  // 分子
int deno;  // 分母
int gcd(int nu, int de);
public:
//构造函数及运算符重载的函数声明
CFraction(int nu = 0, int de = 1):nume(nu), deno(de){};         //构造函数，初始化用

friend CFraction operator + (CFraction &c1,CFraction &c2);
friend CFraction operator - (CFraction &c1,CFraction &c2);
friend CFraction operator * (CFraction &c1,CFraction &c2);
friend CFraction operator / (CFraction &c1,CFraction &c2);

friend CFraction operator - (CFraction &c);

friend CFraction operator + (CFraction &c, int s);
friend CFraction operator - (CFraction &c, int s);
friend CFraction operator * (CFraction &c, int s);
friend CFraction operator / (CFraction &c, int s);

friend CFraction operator + (int s, CFraction &c);
friend CFraction operator - (int s, CFraction &c);
friend CFraction operator * (int s, CFraction &c);
friend CFraction operator / (int s, CFraction &c);

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();                    //化简（使分子分母没有公因子）
void display();
};
//重载函数的实现及用于测试的main()函数
void CFraction::Simplify()
{
int n ;

if(nume < 0  && deno > 0)
{
n = gcd(-nume, deno);
}
else if(nume > 0  && deno > 0)
{
n = gcd(nume, deno);
}
else if(nume > 0  && deno < 0)
{
n = gcd(nume, -deno);
}
else if(nume < 0  && deno < 0)
{
n = -gcd(-nume, -deno);
}
nume = nume / n;

deno = deno / n;

}

int CFraction::gcd(int nu, int de)
{
int t, r, a, b;

a = nu;

b = de;

if (a < b)
{
t = a;
a = b;
b = t;
}
while (b != 0)
{
r = a % b;
a = b;
b = r;
}

return a;
}

void CFraction::display()
{
cout << nume << "/" << deno << endl;
}

CFraction operator + (CFraction &c1,CFraction &c2)
{
CFraction c;

c.nume = c1.nume * c2.deno + c2.nume * c1.deno;

c.deno = c1.deno * c2.deno;

return c;
}

CFraction operator - (CFraction &c1,CFraction &c2)
{
CFraction c;

c.nume = c1.nume * c2.deno - c2.nume * c1.deno;

c.deno = c1.deno * c2.deno;

return c;
}

CFraction operator * (CFraction &c1,CFraction &c2)
{
CFraction c;

c.nume = c1.nume * c2.nume;

c.deno = c1.deno * c2.deno;

return c;
}

CFraction operator / (CFraction &c1,CFraction &c2)
{
CFraction c;

c.nume = c1.nume * c2.deno;

c.deno = c1.deno * c2.nume;

return c;
}

CFraction operator - (CFraction &c)
{
c.nume = 0 - c.nume;
return c;
}

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

}

CFraction operator + (CFraction &c, int s)
{
CFraction c2 = c;

c2.nume = c.nume + s * c.deno;

return c2;
}

CFraction operator - (CFraction &c, int s)
{
CFraction c2 = c;

c2.nume = c.nume - s * c.deno;

return c2;
}

CFraction operator * (CFraction &c, int s)
{
CFraction c2 = c;

c2.nume = c.nume * s;

return c2;
}

CFraction operator / (CFraction &c, int s)
{
CFraction c2 = c;

c2.deno = c.deno * s;

return c2;
}

CFraction operator + (int s, CFraction &c)
{
CFraction c2 = c;

c2.nume = c.nume + s * c.deno;

return c2;
}

CFraction operator - (int s, CFraction &c)
{
CFraction c2 = c;

c2.nume = s * c.deno - c.nume;

return c2;
}

CFraction operator * (int s, CFraction &c)
{

CFraction c2 = c;

c2.nume = s * c.nume;

return c2;
}

CFraction operator / (int s, CFraction &c)
{

CFraction c2 = c;

c2.nume = s * c.deno;

c2.deno = c.nume;

return c2;
}

void main()
{
CFraction c1(-3, -6), c2(2, 7), c;

cout << "c1 =" ;
c1.Simplify();

c1.display();

cout << "c2 =" ;

c2.Simplify();

c2.display();

c = c1 + c2;

c.Simplify();
cout << "c1 + c2 =";

c.display();

c = c1 - c2;

c.Simplify();

cout << "c1 - c2 =";

c.display();

c = c1 * c2;

c.Simplify();
cout << "c1 * c2 =";
c.display();

c = c1 / c2;
c.Simplify();

cout << "c1 / c2 =";

c.display();

c = c1 + 2;

cout << "c1 + 2 =";

c.Simplify();
c.display();

c = 2 - c2;

cout << "2 - c2 =";

c.Simplify();

c.display();

c = c1 * 2;

cout << "c1 * 2 =";

c.Simplify();

c.display();

c = 2 / c2;

cout << "2 / c2 =";

c.Simplify();

c.display();

c = - c1;

cout << "-c1 =";

c.display();

if(c1 > c2)
{
cout << "c1 > c2" << endl;
}
if(c1 < c2)
{
cout << "c1 < c2" << endl;
}
if(c1 >= c2)
{
cout << "c1 ≥ c2" << endl;
}
if(c1 <= c2)
{
cout << "c1 ≤ c2" << endl;
}
if(c1 == c2)
{
cout << "c1 = c2" << endl;
}
if(c1 != c2)
{
cout << "c1 ≠ c2" << endl;
}
system("pause");
}