第八周项目三——分数类中的运算符重载（2）

（2）在（1）的基础上，实现分数类中的对象和整型数的四则运算。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。

/* All rights reserved.
* 文件名称：test.cpp
* 作者：陈丹妮
* 完成日期：2015年 5 月 27 日
* 版 本 号：v1.0
*/

#include <iostream>
#include <cmath>
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();

friend CFraction operator+(const CFraction &c1,const CFraction &c2);  //两个分数相加，结果要化简
friend CFraction operator-(const CFraction &c1,const CFraction &c2);  //两个分数相减，结果要化简
friend CFraction operator*(const CFraction &c1,const CFraction &c2);   //两个分数相乘，结果要化简
friend CFraction operator/(const CFraction &c1,const CFraction &c2);   //两个分数相除，结果要化简

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

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

CFraction operator+();  //取正一目运算
CFraction operator-();  //取反一目运算,即，取相反数

//判断两个分数的大小
friend bool operator>(const CFraction &c1,const CFraction &c2);
friend bool operator<(const CFraction &c1,const CFraction &c2);
friend bool operator==(const CFraction &c1,const CFraction &c2);
friend bool operator>=(const CFraction &c1,const CFraction &c2);
friend bool operator<=(const CFraction &c1,const CFraction &c2);
friend bool operator!=(const CFraction &c1,const CFraction &c2);

friend bool operator>(const CFraction &c,int m);
friend bool operator<(const CFraction &c,int m);
friend bool operator==(const CFraction &c,int m);
friend bool operator>=(const CFraction &c,int m);
friend bool operator<=(const CFraction &c,int m);
friend bool operator!=(const CFraction &c,int m);

friend bool operator>(int m,const CFraction &c);
friend bool operator<(int m,const CFraction &c);
friend bool operator==(int m,const CFraction &c);
friend bool operator>=(int m,const CFraction &c);
friend bool operator<=(int m,const CFraction &c);
friend bool operator!=(int m,const CFraction &c);

};\

//分数化简
void CFraction::simplify()
{
int m,n,r;
n=fabs(nume);  //分子
m=fabs(deno);  //分母
while(n!=0)   //while(r=m%n)  求m,n的最大公约数
{
//{ m=n;
r=m%n;    //  n=r;}
m=n;      // deno/=n;
n=r;      // nume/=n;
}
deno/=m;     //化简分数
nume/=m;
if(deno<0)   //// 将分母转化为正数
{
deno=-deno;
nume=-nume;
}
}
//显示分数
void CFraction::display()
{
cout<<"("<<nume<<"/"<<deno<<")"<<endl; //(分子/分母)的形式
}
//分数相加
CFraction operator+(const CFraction &c1,const CFraction &c2)
{
CFraction t;
t.nume=c1.nume*c2.deno+ c1.deno*c2.nume;
t.deno=c1.deno*c2.deno;
t.simplify();
return t;
}
//分数相减
CFraction operator-(const CFraction &c1,const CFraction &c2)
{
CFraction t;
t.nume=c1.nume*c2.deno- c1.deno*c2.nume;
t.deno=c1.deno*c2.deno;
t.simplify();
return t;
}
//分数相乘
CFraction operator*(const CFraction &c1,const CFraction &c2)
{
CFraction t;
t.nume=c1.nume*c2.nume;
t.deno=c1.deno*c2.deno;
t.simplify();
return t;
}
//分数相除
CFraction operator/(const CFraction &c1,const CFraction &c2)
{
CFraction t;
if (!c2.nume) return c1;   //除法无效时，这种情况需要考虑，但这种处理仍不算合理
t.nume=c1.nume*c2.deno;
t.deno=c1.deno*c2.nume;
t.simplify();
return t;
}

CFraction operator+(const CFraction &c,int m)
{
CFraction t(c.nume+m*c.deno,c.deno);
t.simplify();
return t;
}

CFraction operator-(const CFraction &c,int m)
{
CFraction t(c.nume-m*c.deno,c.deno);
t.simplify();
return t;
}

CFraction operator*(const CFraction &c,int m)
{
CFraction t(c.nume*m,c.deno);
t.simplify();
return t;
}

CFraction operator/(const CFraction &c,int m)
{
CFraction t(c.nume,c.deno*m);
t.simplify();
return t;
}

CFraction operator+(int m,const CFraction &c)
{
CFraction t(c.nume+m*c.deno,c.deno);
t.simplify();
return t;
}

CFraction operator-(int m,const CFraction &c)
{
CFraction t(m*c.deno-c.nume,c.deno);
t.simplify();
return t;
}

CFraction operator*(int m,const CFraction &c)
{
CFraction t(m*c.nume,c.deno);
t.simplify();
return t;
}

CFraction operator/(int m,const CFraction &c)
{
CFraction t(m*c.deno,c.nume);
t.simplify();
return t;
}

CFraction CFraction::operator+()
{
return *this;
}
CFraction CFraction::operator-()
{
CFraction c;
c.nume=-nume;
return c;
}

// 分数比较大小
bool operator>(const CFraction &c1,const CFraction &c2)
{
int c1_nume,c2_nume,common_deno;
c1_nume=c1.nume*c2.deno;        // 计算分数通分后的分子，同分母为deno*c.deno
c2_nume=c2.nume*c1.deno;
common_deno=c1.deno*c2.deno;
if ((c1_nume>c2_nume&&common_deno>0)||(c1_nume<c2_nume&&common_deno<0)) return true; // 将通分后的分子比较大小
return false;
}
// 分数比较大小
bool operator<(const CFraction &c1,const CFraction &c2)
{
int c1_nume,c2_nume,common_deno;
c1_nume=c1.nume*c2.deno;        // 计算分数通分后的分子，同分母为deno*c.deno
c2_nume=c2.nume*c1.deno;
common_deno=c1.deno*c2.deno;
if ((c1_nume-c2_nume)*common_deno<0) return true;
return false;
}
bool operator==(const CFraction &c1,const CFraction &c2)
{
if (c1!=c2) return false;
return true;
}
bool operator!=(const CFraction &c1,const CFraction &c2)
{
if (c1>c2 || c1<c2) return true;
return false;
}
bool operator>=(const CFraction &c1,const CFraction &c2)
{
if (c1<c2) return false;
return true;
}
bool operator<=(const CFraction &c1,const CFraction &c2)
{
if (c1>c2) return false;
return true;
}

bool operator>(const CFraction &c,int m)
{
if(c.deno>0)
return c.nume>(m*c.deno);
else
return c.nume<(m*c.deno);
}
bool operator<(const CFraction &c,int m)
{
if(c.deno>0)
return c.nume<(m*c.deno);
else
return c.nume>(m*c.deno);
}
bool operator==(const CFraction &c,int m)
{
return c.nume==(m*c.deno);
}
bool operator!=(const CFraction &c,int m)
{
return c.nume!=(m*c.deno);
}
bool operator>=(const CFraction &c,int m)
{
return !(c<m);
}
bool operator<=(const CFraction &c,int m)
{
return !(c>m);
}

bool operator>(int m,const CFraction &c)
{
if(c.deno>0)
return (m*c.deno)>c.nume;
else
return (m*c.deno)<c.nume;
}
bool operator<(int m,const CFraction &c)
{
if(c.deno>0)
return (m*c.deno)<c.nume;
else
return (m*c.deno)>c.nume;
}
bool operator==(int m,const CFraction &c)
{
return c.nume==(m*c.deno);
}
bool operator!=(int m,const CFraction &c)
{
return c.nume!=(m*c.deno);
}
bool operator>=(int m, const CFraction &c)
{
return !(m<c);
}
bool operator<=(int m, const CFraction &c)
{
return !(m>c);
}

int main()
{
CFraction x(1,3),y(-5,10),s;
cout<<"分数x=1/3      y=-5/10"<<endl;
s=+x+y;
cout<<"+x+y=";
s.display();
s=x-y;
cout<<"x-y=";
s.display();
s=x*y;
cout<<"x*y=";
s.display();
s=x/y;
cout<<"x/y=";
s.display();
s=-x+y;
cout<<"-x+y=";
s.display();

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

CFraction c1(5,3),c2;
c2=c1+5;
cout<<"c2=";
c2.display();
c2=5+c1;
cout<<"c2=";
c2.display();
c2=c1-5;
cout<<"c2=";
c2.display();
c2=5-c1;
cout<<"c2=";
c2.display();

c2=c1*5;
cout<<"c2=";
c2.display();
c2=5*c1;
cout<<"c2=";
c2.display();

c2=c1/5;
cout<<"c2=";
c2.display();
c2=5/c1;
cout<<"c2=";
c2.display();

return 0;
}

学习心得：代码大体的知道怎么弄，就是有点内容多，实际不是很难，谢谢老师的模板，下次尝试写写没有模板的程序。继续努力吧！