学步园

/* (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：分数类                               
* 作    者：冯珍珍                                
* 完成日期：  2012   年   4   月    16 日   
* 版 本 号：略              
* 对任务及求解方法的描述部分   
* 输入描述：   
* 问题描述： 在任务3的基础上拓展。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。例如：CFraction a(1,3),b; int i=2; 可以完成b=a+i;。同样，可以完成i+a, 45+a, a*27, 5/a等各种运算。  
* 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
public:
 CFraction(int nu=0,int de=1):nume(nu),deno(de){}
 void simplify();
 void display();
//以下为用友员函数实现分数与整数的四则运算的函数声明部分
 friend CFraction operator+(int i, const CFraction &c);  //新加方法
 friend CFraction operator-(int i, const CFraction &c);  //新加方法
 friend CFraction operator*(int i, const CFraction &c);  //新加方法
 friend CFraction operator/(int i, const CFraction &c);  //新加方法
 friend CFraction operator+(const CFraction &c, int i);  //新加方法
 friend CFraction operator-(const CFraction &c, int i);  //新加方法
 friend CFraction operator*(const CFraction &c, int i);  //新加方法
 friend CFraction operator/(const CFraction &c, int i);  //新加方法

 CFraction operator+();  //取正一目运算
 CFraction operator-();  //取反一目运算
 bool operator>(const CFraction &c);
 bool operator<(const CFraction &c);
 bool operator==(const CFraction &c);
 bool operator!=(const CFraction &c);
 bool operator>=(const CFraction &c);
 bool operator<=(const CFraction &c);
};

// 分数化简
void CFraction::simplify()
{
 int m, n, r;
 m=abs(deno);
 n=abs(nume);
 while(r=m%n) 
 {
  m=n;
  n=r;
 }
 deno /= n;    
 nume /= n;
 if (deno < 0)  
 {
  deno =- deno;
  nume =- nume;
 }
}

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

CFraction CFraction:: operator+()
{
 return *this;
}

CFraction CFraction:: operator-()
{
 CFraction x;

 x.nume = -nume;

 x.deno = deno;

 return x;     
}

bool CFraction::operator>(const CFraction &c)
{
 int n, a, d;

 n = nume * c.deno;

 a = c.nume * deno; 

 d = deno * c.deno;

 if (n > a && d > 0 || n < a && d < 0)
 {
  return true;
 }

 return false;
}

bool CFraction::operator<(const CFraction &c)
{
 int n, a, d;

 n = nume * c.deno;  

 a = c.nume * deno;

 d = deno * c.deno;

 if ((n - a) * d < 0)
 {
  return true;
 }
 else
 {
  return false;
 }
}

bool CFraction::operator==(const CFraction &c)
{
 if (*this!=c)
 {
  return false;
 }
 else
 {
  return true;
 }
}

bool CFraction::operator!=(const CFraction &c)
{
 if (*this > c || *this < c)
 {
  return true;
 }
 else
 {
  return false;
 }
}

bool CFraction::operator>=(const CFraction &c)
{
 if (*this<c) 
 {
  return false;
 }
 else
 {
  return true;
 }
}

bool CFraction::operator<=(const CFraction &c)
{
 if (*this > c) 
 {
  return false;
 }
 else
 {
  return true;
 }
}

//新加方法：
CFraction operator+ (const CFraction &c, int i)
{
 CFraction t;

 t.nume = c.nume  + c.deno * i;

 t.deno = c.deno;

 t.simplify();

 return t;
}

CFraction operator- (const CFraction &c, int i)
{
 CFraction t;

 t.nume = c.nume - i * c.deno;

 t.deno = c.deno;

 t.simplify();

 return t;
}

CFraction operator* (const CFraction &c, int i)
{
 CFraction t;

 t.nume = c.nume * i;

 t.deno = c.deno;

 t.simplify();

 return t;
}

CFraction operator/(const CFraction &c, int i)
{
 CFraction t;

 t.deno *= i;

 t.nume = c.nume;

 t.simplify();

 return t;
}

 

 

CFraction operator+ (int i, const CFraction &c)
{
 CFraction t;

 t.nume = c.nume  + c.deno * i;

 t.deno = c.deno;

 t.simplify();

 return t;
}

CFraction operator- (int i, const CFraction &c)
{
 CFraction t;

 t.nume = c.nume - i * c.deno;

 t.deno = c.deno;

 t.simplify();

 return t;
}

CFraction operator* (int i, const CFraction &c)
{
 CFraction t;

 t.nume = c.nume * i;

 t.deno = c.deno;

 t.simplify();

 return t;
}

CFraction operator/(int i, const CFraction &c)
{
 CFraction t;

 t.deno *= i;

 t.nume = c.nume;

 t.simplify();

 return t;
}

 

int main()
{
 CFraction x(1,3),y(-5,10),s;

 x.display();
 y.display();
 if (x>y) cout<<"x大于y"<<endl;
 if (x<y) cout<<"x小于y"<<endl;
 if (x==y) cout<<"x等于y"<<endl;
 
 cout<<endl;

 cout << "分数与整数相加的实现：" << endl;
 cout << "x + 5 = ";
 s = x + 5;
 s.display();
 cout << "5 + x = " ;
 s = 5 + x;
 s.display();
 cout << "x - 5 = " ;
 s = x - 5;
 s.display();
 cout << "5 - x = " ;
 s = 5 - x;
 s.display();
 cout << "x / 5 = " ;
 s = x / 5;
 s.display();
 cout << "5 / x = " ;
 s = 5 / x;
 s.display();
 cout << "x * 5 = " ;
 s = x * 5;
 s.display();
 cout << "5 * x = " ;
 s = 5 * x;
 s.display();
 
 system("pause");
 return 0;
}