C++第8周项目4 -分数类和整型数的四则运算

课程首页地址：http://blog.csdn.net/sxhelijian/article/details/7910565，本周题目链接：http://blog.csdn.net/sxhelijian/article/details/8806111

【项目4-分数类和整型数的四则运算】在项目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。

参考解答：

#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();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);};// 分数化简void CFraction::simplify(){int m,n,r;m=abs(deno);n=abs(nume);while(r=m%n)  // 求m，n的最大公约数{m=n;n=r;}deno/=n;     // 化简nume/=n;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;}// 分数相加CFraction operator+(const CFraction &c1, const CFraction &c2){CFraction t;t.nume=c1.nume*c2.deno+c2.nume*c1.deno;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-c2.nume*c1.deno;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;t.nume=c1.nume*c2.deno;t.deno=c1.deno*c2.nume;t.simplify();return t;}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;}// 分数取正号CFraction CFraction:: operator+(){return *this;}// 分数取负号CFraction CFraction:: operator-(){CFraction c;c.nume=-nume;c.deno=-deno;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c1.deno*c2.denoc2_nume=c2.nume*c1.deno; common_deno=c1.deno*c2.deno;//if (c1_nume>c2_nume) return true; 无法应对common_deno<0的情形//下面的语句更简练的一种写法if ((c1_nume-c2_nume)*common_deno>0) return true;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;      c2_nume=c2.nume*c1.deno;common_deno=c1.deno*c2.deno;if ((c1_nume-c2_nume)*common_deno<0) return true; return false;}// 分数比较大小bool operator==(const CFraction &c1, const CFraction &c2){if (c1!=c2) return false;return true;}// 分数比较大小bool operator!=(const CFraction &c1, const CFraction &c2){if (c1>c2 || c1<c2) return true;return false;}// 分数比较大小bool operator>=(const CFraction &c1, const CFraction &c2){if (c1<c2) return false;return true;}// 分数比较大小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(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;//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;}