第八周项目3——分数类中的运算符重载（四则运算）

（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。

代码如下：

#include <iostream>int gcd(int m,int n);using namespace std;class CFraction{private:    int nume;  // 分子    int deno;  // 分母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) {}    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 i);    friend CFraction operator+(int i, const CFraction &c );    friend CFraction operator-(const CFraction &c, int i);    friend CFraction operator-(int i, const CFraction &c );    friend CFraction operator*(const CFraction &c, int i);    friend CFraction operator*(int i, const CFraction &c );    friend CFraction operator/(const CFraction &c, int i);    friend CFraction operator/(int i, const CFraction &c );    CFraction operator+();  //取正一目运算    CFraction operator-();  //取反一目运算    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 i);    friend bool operator>(int i, const CFraction &c);    friend bool operator<(const CFraction &c, int i);    friend bool operator<(int i, const CFraction &c);    friend bool operator==(const CFraction &c, int i);    friend bool operator==(int i, const CFraction &c);    friend bool operator!=(const CFraction &c, int i);    friend bool operator!=(int i, const CFraction &c);    friend bool operator>=(const CFraction &c, int i);    friend bool operator>=(int i, const CFraction &c);    friend bool operator<=(const CFraction &c, int i);    friend bool operator<=(int i, const CFraction &c);};//重载函数的实现及用于测试的main()函数int gcd(int m,int n){    int t;    if(m<n)    {        t=m;        m=n;        n=t;    }    while(t=m%n)    {        m=n;        n=t;    }     return n;}void CFraction::simplify(){    int n=gcd(nume,deno);    nume/=n;    deno/=n;}void CFraction::display(){    cout<<"("<<nume<<"/"<<deno<<")"<<endl;}CFraction operator+(const CFraction &c1, const CFraction &c2){    CFraction z;    z.nume=c1.nume*c2.deno+c2.nume*c1.deno;    z.deno=c1.deno*c2.deno;    z.simplify();    return z;}CFraction operator-(const CFraction &c1, const CFraction &c2){    CFraction z;    z.nume=c1.nume*c2.deno-c2.nume*c1.deno;    z.deno=c1.deno*c2.deno;    z.simplify();    return z;}CFraction operator*(const CFraction &c1, const CFraction &c2){    CFraction z;    z.nume=c1.nume*c2.nume;    z.deno=c1.deno*c2.deno;    z.simplify();    return z;}CFraction operator/(const CFraction &c1, const CFraction &c2){    CFraction z;    if(c2.nume==0)        return c1;    z.nume=c1.nume*c2.deno;    z.deno=c1.deno*c2.nume;    z.simplify();    return z;}CFraction operator+(const CFraction &c, int i){    CFraction c1(c.nume+i*c.deno,c.deno);    c1.simplify();    return c1;}CFraction operator+(int i, const CFraction &c ){    CFraction c1(c.nume+i*c.deno,c.deno);    c1.simplify();    return c1;}CFraction operator-(const CFraction &c, int i){    CFraction c1(c.nume-i*c.deno,c.deno);    c1.simplify();    return c1;}CFraction operator-(int i, const CFraction &c ){    CFraction c1(i*c.deno-c.nume,c.deno);    c1.simplify();    return c1;}CFraction operator*(const CFraction &c, int i){    CFraction c1(c.nume*i,c.deno);    c1.simplify();    return c1;}CFraction operator*(int i, const CFraction &c ){    CFraction c1(c.nume*i,c.deno);    c1.simplify();    return c1;}CFraction operator/(const CFraction &c, int i){    CFraction c1(c.nume,c.deno*i);    c1.simplify();    return c1;}CFraction operator/(int i, const CFraction &c ){    CFraction c1(i*c.deno,c.nume);    c1.simplify();    return c1;}CFraction CFraction:: operator+(){    return *this;}CFraction CFraction:: operator-(){    CFraction c;    c.nume=-nume;    c.deno=-deno;    return c;}bool operator>(const CFraction &c1, const CFraction &c2){    int c1_nume,c2_nume,com_deno;    c1_nume=c1.nume*c2.deno;    c2_nume=c2.nume*c1.deno;    com_deno=c1.deno*c2.deno;    if((c1_nume-c2_nume)*com_deno>0) return true;    return false;}bool operator<(const CFraction &c1, const CFraction &c2){    int c1_nume,c2_nume,com_deno;    c1_nume=c1.nume*c2.deno;    c2_nume=c2.nume*c1.deno;    com_deno=c1.deno*c2.deno;    if((c1_nume-c2_nume)*com_deno<0) return true;    return false;}bool operator==(const CFraction &c1, const CFraction &c2){    if(c1<c2||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 &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 i){    if(c.deno>0)        return c.nume>(i*c.deno);    else        return c.nume<(i*c.deno);}bool operator>(int i, const CFraction &c){    if(c.deno>0)        return (i*c.deno)>c.nume;    else        return (i*c.deno)<c.nume;}bool operator<(const CFraction &c, int i){    if(c.deno>0)        return c.nume<(i*c.deno);    else        return c.nume>(i*c.deno);}bool operator<(int i, const CFraction &c){    if(c.deno>0)        return (i*c.deno)<c.nume;    else        return (i*c.deno)>c.nume;}bool operator==(const CFraction &c, int i){    return c.nume==(i*c.deno);}bool operator==(int i, const CFraction &c){    return c.nume==(i*c.deno);}bool operator!=(const CFraction &c, int i){    return c.nume!=(i*c.deno);}bool operator!=(int i, const CFraction &c){    return c.nume!=(i*c.deno);}bool operator>=(const CFraction &c, int i){    return !(c<i);}bool operator>=(int i, const CFraction &c){    return !(i<c);}bool operator<=(const CFraction &c, int i){    return !(c>i);}bool operator<=(int i, const CFraction &c){    return !(i>c);}int main(){    CFraction x(10,5),y(3,9),s;    x.display();    y.display();    cout<<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();    if (x>y) cout<<"大于"<<endl;    if (x<y) cout<<"小于"<<endl;    if (x==y) cout<<"等于"<<endl;    if (x>=y) cout<<"大于等于"<<endl;    if (x<=y) cout<<"小于等于"<<endl;    if (x!=y) cout<<"不等于"<<endl;    cout<<endl;     CFraction c1(5,3),c2;    //以下建议在调试环境中完成测试，    c2=c1+5;    c2=5+c1;    c2=c1-5;    c2=5-c1;    c2=c1*5;    c2=5*c1;    c2=c1/5;    c2=5/c1;    bool b;    b=(c1>2);    b=(2>c1);    return 0;}

总结：我也是醉了，坚持编完已经是很了不起了。可惜没有单步执行下次再来；