C++ Complex类运算符重载

所谓重载,就是重新赋予新的含义｡

函数重载就是对一个已有的函数赋予新的含义,使之实现新功能｡运算符也可以重载｡实际上,我们已经在不知不觉之中使用了运算符重载｡

现在要讨论的问题是: 用户能否根据自己的需要对C++已提供的运算符进行重载,赋予它们新的含义,使之一名多用｡譬如,能否用“+”号进行两个复数的相加｡在C++中不能在程序中直接用运算符“+”对复数进行相加运算｡用户必须自己设法实现复数相加｡

例如：1.  编写一个简单复数类SComplex，要求用友元函数重载"+"、"-"、"*"、"/"、 "<<"、">>"运算符，

用成员函数重载"="运算符，使之能够实现整数或浮点数和复数的四则运算和标准流的输入输出，并且进行测试。

#include<iostream>

#include<iomanip>

using namespace std;

class SComplex

{

public:

　　 double img,real;

public:

 

    //SComplex(){} //无参构造函数

 

       SComplex(double x=0,double y=0) //有参构造函数

 

       {

 

        real=x;

 

        img=y;

 

    }

 

       void print();

 

       friend SComplex operator+(const SComplex&c1,SComplex&c2);

 

      friend SComplex operator-( SComplex&c1,SComplex&c2);

 

      friend SComplex operator*( SComplex&c1,SComplex&c2);

 

     friend SComplex operator/( SComplex&c1,SComplex&c2);

 

     SComplex& operator=(const SComplex &);

 

     friend ostream& operator << (ostream&,SComplex&);  //运算符“<<”重载为友元函数

 

     friend istream& operator >> (istream&,SComplex&);  //运算符“>>”重载为友元函数

    SComplex add(SComplex &c1,SComplex &c2);    //自定义加法运算

 

    SComplex operator++();      //自加运算

 

};

 

void SComplex::print()

 

{

       cout<<showpos<<real<<showpos<<img<<"i"<<"\n"<<endl;

}

 

SComplex operator+(const SComplex &c1,SComplex &c2)

{

　　　　  SComplex temp(c1.real+c2.real,c1.img+c2.img);

 

              return temp;

 

}

 

SComplex operator-( SComplex &c1,SComplex &c2)

 

{

 

        SComplex temp;

 

        temp.real=c1.real-c2.real;

 

        temp.img=c1.img-c2.img;

 

        return temp;       

 

}

 

SComplex::SComplex add(SComplex &c1,SComplex &c2)

 

{

 

        SComplex temp;

 

        temp.real=c1.real+c2.real;

 

        temp.img=c1.img+c2.img;

 

        return temp;     

 

}

 

SComplex:: SComplex operator*(SComplex &c1,SComplex &c2)

 

{

 

        SComplex temp;

 

        temp.real=c1.real*c2.real-c1.img*c2.img;

 

        temp.img=c1.real*c2.img+c1.img*c2.real;

 

        return temp;

 

}

 

SComplex::SComplex operator/(SComplex &c1,SComplex &c2)

 

{

 

         SComplex temp;

 

         temp.real=c1.real/c2.real;

 

         temp.img =c1.img/c2.real;

 

         return temp;                  

 

}

 

SComplex& SComplex::operator=(const SComplex &c)

 

{

 

          this->real=c.real;

 

          this->img=c.img;

 

          return *this;                  

 

}

 

SComplex SComplex:: operator++()

 

{ 

 

         real++;

 

         img++;

 

         return *this;             

 

}

 

ostream& operator << (ostream& output,SComplex& c) //定义运算符“<<”重载函数

 

{

 

        if(c.real==0)

 

        {

 

            output<<c.img<<"i"<<endl;

 

        }

 

        if(c.img==0)

 

        {

 

            output<<c.real<<endl;

 

        }

 

        else if(c.real!=0&&c.img!=0)

 

        {

 

         output<<c.real<<c.img<<"i"<<endl;

 

        }

 

        return output;

 

}

 

istream& operator >> (istream& input,SComplex& c)  //定义重载运算符“>>”

 

{

 

   cout<<"input real and img number:"<<endl;

 

   input>>c.real>>c.img;

 

   return input;

 

}

 

int main()

 

{

 

       SComplex c1(2,8),c2(4,-2),c3;

 

      

 

       cout<<"复数： c1="<<setw(2);

 

       c1.print();

 

       cout<<"复数： c2="<<setw(2);

 

       c2.print();

 

      cout<<setw(6);

 

   

 

       cout<<"重载加法：c1+c2=";

 

       c3=c1+c2;

 

       c3.print();

 

      

 

       cout<<"重载输出 ";

 

       cout<<"c1+c2=";

 

       cout<<c3;

 

       cout<<endl;

 

      

 

       cout<<"重载减法： c1-c2=";

 

       c3=c1-c2;

 

       c3.print();

 

      

 

       cout<<"调用加法函数：";

 

      c3=add(c1,c2);

 

       cout<<"c1+c2=";

 

       c3.print();

 

      

 

       cout<<"重载乘法： c1*c2=";

 

       c3=c1*c2;

 

       c3.print();

 

      

 

       cout<<"重载除法： c1/c2=";

 

       c3=c1/c2;

 

      

 

       c3.print();

 

       cout<<"重载等号： c3=";

 

       c3=c1;

 

       c3.print();

 

       cout<<"重载自加： c1++=";

 

       c3=++c2;

 

       c3.print();

 

      

 

       cout<<"重载输出： ";

 

       cout<<c3;

 

       cout<<"重载输入:"<<endl;

 

       cin>>c1;

 

       cout<<c1;

 

       system("pause");

 

       return 0;

 

}