第九周项目3——分数类中的运算符重载（续）

问题及代码：

/**Copyright (c)2015,烟台大学计算机与控制工程学院*All rights reserved.*文件名称：cfraction.cpp*作    者：赵敏*完成日期：2015年5月14日*版 本 号：v1.0**问题描述：1）定义分数的一目运算+和-，分别代表分数取正和求反，将“按位取反运算符”~重载为分数的求倒数运算。（2）定义分数类中<<和>>运算符重载，实现分数的输入输出，改造原程序中对运算结果显示方式，使程序读起来更自然。*/#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);   //构造函数，初始化用    void simplify();    //构造函数及运算符重载的函数声明    int gcd(int,int);    CFraction operator+(const CFraction &c);    CFraction operator-(const CFraction &c);    CFraction operator*(const CFraction &c);    CFraction 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);    bool operator<=(const CFraction &c);    friend istream &operator>>(istream &input,CFraction &x);    friend ostream &operator<<(ostream &output,CFraction x);    CFraction operator+();  //取正    CFraction operator-();  //取反    CFraction operator~();  //取倒数};//重载函数的实现及用于测试的main()函数CFraction::CFraction(int nu,int de){    if(de!=0)    {    nume=nu;    deno=de;    }}void CFraction::simplify(){    int a=gcd(nume,deno);    nume=nume/a;    deno=deno/a;}int CFraction::gcd(int m, int n){    int r;    do    {        r=m%n;        m=n;        n=r;    }while(r!=0);    return m;}CFraction CFraction::operator+(const CFraction &c){   CFraction t;   t.nume=nume*c.deno+deno*c.nume;   t.deno=deno*c.deno;    t.simplify();    return t;}CFraction CFraction::operator-(const CFraction &c){   CFraction t;   t.nume=nume*c.deno-deno*c.nume;   t.deno=deno*c.deno;    t.simplify();    return t;}CFraction CFraction::operator*(const CFraction &c){  CFraction t;   t.nume=nume*c.nume;   t.deno=deno*c.deno;    t.simplify();    return t;}CFraction CFraction::operator/(const CFraction &c){  CFraction t;  if (!c.nume) return *this;   t.nume=nume*c.deno;   t.deno=deno*c.nume;    t.simplify();    return t;}bool CFraction::operator>(const CFraction &c){  int this_nume,c_nume,common_deno;    this_nume=nume*c.deno;    c_nume=c.nume*deno;    common_deno=deno*c.deno;    if ((this_nume>c_nume&&common_deno>0)||(this_nume<c_nume&&common_deno<0)) return true;    return false;}bool CFraction::operator<(const CFraction &c){  int this_nume,c_nume,common_deno;    this_nume=nume*c.deno;    c_nume=c.nume*deno;    common_deno=deno*c.deno;    if ((this_nume<c_nume&&common_deno>0)||(this_nume>c_nume&&common_deno<0)) return true;    return false;}bool CFraction::operator==(const CFraction &c){   if(*this!=c)return false;   return true;}bool CFraction::operator!=(const CFraction &c){   if(*this<c||*this>c)return false;   return true;}bool CFraction::operator>=(const CFraction &c){    if(*this<c)return false;    return true;}bool CFraction::operator<=(const CFraction &c){    if(*this>c)return false;    return true;}istream &operator>>(istream &input,CFraction &x){    char c;    do{            cout<<"input cfraction: ";   input>>x.nume>>c>>x.deno;    }while(!(c=='/'));    return input;}ostream &operator<<(ostream &output,CFraction x){    output<<x.nume<<"/"<<x.deno;    return output;}CFraction CFraction:: operator+(){    return *this;}CFraction CFraction:: operator-(){    CFraction x;    x.nume=-nume;    x.deno=deno;    return x;}CFraction CFraction:: operator~(){    CFraction x;    x.nume=deno;    x.deno=nume;    if(x.deno<0)    {        x.deno=-x.deno;        x.nume=-x.nume;    }    return x;}int main(){    CFraction x,y,s;    cin>>x>>y;    cout<<"分数x=1/3      y=-5/10"<<endl;    s=x+y;    cout<<"x+y=";    cout<<s<<endl;    s=x-y;    cout<<"x-y=";    cout<<s<<endl;;    s=x*y;    cout<<"x*y=";    cout<<s<<endl;    s=x/y;    cout<<"x/y=";    cout<<s<<endl;    cout<<x<<endl;    if (x>y) cout<<"大于"<<endl;    if (x<y) cout<<"小于"<<endl;    if (x==y) cout<<"等于"<<endl;    cout<<y;    cout<<endl;

    return 0;}

运行结果：

知识点总结：

重载单目运算符