第八周实验指导任务1--实现复数类中的运算符重载

/* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2011, 烟台大学计算机学院学生 
* All rights reserved.
* 文件名称：定义一个复数类重载运算符+、-、*、/，使之能用于复数的加减乘除。

* 作    者：         雷恒鑫                       
* 完成日期：     2012    年 04      月  05    日
* 版 本 号：       V1.0   
* 对任务及求解方法的描述部分
* 输入描述： 
* 问题描述： 
* 程序输出： 

* 程序头部的注释结束

*/

方案一：用类的成员函数完成运算符的重载：

#include<iostream>using namespace std;class Complex{public:Complex(){real=0;imag=0;}Complex(double r,double i){real=r;imag=i;}Complex operator+(Complex &c2);Complex operator-(Complex &c2);Complex operator*(Complex &c2);Complex operator/(Complex &c2);void display();private:double real;double imag;};//下面定义成员函数//复数相加： (a+bi)+(c+di)=(a+c)+(b+d)i.Complex Complex::operator+(Complex &c2)    {      Complex c;       c.real=real+c2.real;      c.imag=imag+c2.imag;      return c;  }      //复数相减：(a+bi)-(c+di)=(a-c)+(b-d)i.      Complex Complex::operator-(Complex &c2)      {          Complex c;          c.real=real-c2.real;          c.imag=imag-c2.imag;          return c;      }          //复数相乘：(a+bi)(c+di)=(ac－bd)+(bc+ad)i.     Complex Complex::operator*(Complex &c2) {          Complex  c;          c.real=real*c2.real-imag*c2.imag;          c.imag=imag*c2.real+real*c2.imag;          return c;      }          //复数相除：(a+bi)/(c+di)=(ac+bd)/(c^2+d^2) +(bc-ad)/(c^2+d^2)i  Complex Complex::operator/(Complex &c2) {          Complex  c;          double d=c2.real*c2.real+c2.imag*c2.imag;      c.real=(real*c2.real+imag*c2.imag)/d;     //此处有危险未排除：除法溢出      c.imag=(imag*c2.real-real*c2.imag)/d;          return c;      }        void Complex::display( )    {      cout<<"("<<real<<","<<imag<<"i)"<<endl;  }  int main(){Complex c1(3,4),c2(5,-10),c3;cout<<"c1=";c1.display();cout<<"c2=";c2.display();c3=c1+c2;cout<<"c1+c2=";c3.display();c3=c1-c2;cout<<"c1-c2=";c3.display();c3=c1*c2;cout<<"c1*c2=";c3.display();c3=c1/c2;cout<<"c1/c2=";c3.display();system("pause");return 0;}

运行结果：

 

方案二：请用类的友元函数，而不是成员函数，完成上面提及的运算符的重载：

#include<iostream>using namespace std;class Complex{public:Complex(){real=0;imag=0;}Complex(double r,double i){real=r;imag=i;}friend Complex operator+(Complex &c1,Complex &c2);friend Complex operator-(Complex &c1,Complex &c2);friend Complex operator*(Complex &c1,Complex &c2);friend Complex operator/(Complex &c1,Complex &c2);friend void display(Complex &c2);private:double real;double imag;};//下面定义友元函数//复数相加： (a+bi)+(c+di)=(a+c)+(b+d)i.Complex operator+(Complex &c1,Complex &c2)    {      Complex c;       c.real=c1.real+c2.real;      c.imag=c1.imag+c2.imag;      return c;  }      //复数相减：(a+bi)-(c+di)=(a-c)+(b-d)i.      Complex operator-(Complex &c1,Complex &c2)      {          Complex c;          c.real=c1.real-c2.real;          c.imag=c1.imag-c2.imag;          return c;      }          //复数相乘：(a+bi)(c+di)=(ac－bd)+(bc+ad)i.     Complex operator*(Complex &c1,Complex &c2) {          Complex  c;          c.real=c1.real*c2.real-c1.imag*c2.imag;          c.imag=c1.imag*c2.real+c1.real*c2.imag;          return c;      }          //复数相除：(a+bi)/(c+di)=(ac+bd)/(c^2+d^2) +(bc-ad)/(c^2+d^2)i  Complex operator/(Complex &c1,Complex &c2) {          Complex  c;          double d=c2.real*c2.real+c2.imag*c2.imag;      c.real=(c1.real*c2.real+c1.imag*c2.imag)/d;     //此处有危险未排除：除法溢出      c.imag=(c1.imag*c2.real-c1.real*c2.imag)/d;          return c;      }        void display(Complex &c2)    {      cout<<"("<<c2.real<<","<<c2.imag<<"i)"<<endl;  }  int main(){Complex c1(3,4),c2(5,-10),c3;cout<<"c1=";display(c1);cout<<"c2=";display(c2);c3=c1+c2;cout<<"c1+c2=";display(c3);c3=c1-c2;cout<<"c1-c2=";display(c3);c3=c1*c2;cout<<"c1*c2=";display(c3);c3=c1/c2;cout<<"c1/c2=";display(c3);system("pause");return 0;}

运行结果：

 

方案三：在方案二的基础上，扩展+、-、*、/运算符的功能，使之能与double型数据进行运算。设Complex c; double d; c?d和d?c的结果为将d视为实部为d的复数同c运算的结果（其中?为+、-、*、/之一）。另外，定义一目运算符-，-c相当于0-c。

#include<iostream>using namespace std;class Complex{public:Complex(){real=0;imag=0;}Complex(double r,double i){real=r;imag=i;}friend Complex operator+(Complex &c1,Complex &c2);friend Complex operator-(Complex &c1,Complex &c2);friend Complex operator-(Complex &c2);friend Complex operator*(Complex &c1,Complex &c2);friend Complex operator/(Complex &c1,Complex &c2);friend Complex operator+(Complex &c1,const double &d);friend Complex operator+(const double &d, Complex &c);friend void display(Complex &c2);private:double real;double imag;};//下面定义友元函数//复数相加： (a+bi)+(c+di)=(a+c)+(b+d)i.Complex operator+(Complex &c1,Complex &c2)    {      Complex c;       c.real=c1.real+c2.real;      c.imag=c1.imag+c2.imag;      return c;  }  Complex operator+(Complex &c1,const double &d){return Complex(c1.real+d, c1.imag);}Complex operator+(const double &d, Complex &c1){return Complex(c1.real+d, c1.imag);}  //复数相减：(a+bi)-(c+di)=(a-c)+(b-d)i.      Complex operator-(Complex &c1,Complex &c2)      {          Complex c;          c.real=c1.real-c2.real;          c.imag=c1.imag-c2.imag;          return c;      }      Complex operator-(Complex &c2){return Complex(-c2.real, -c2.imag);}//复数相乘：(a+bi)(c+di)=(ac－bd)+(bc+ad)i.     Complex operator*(Complex &c1,Complex &c2) {          Complex  c;          c.real=c1.real*c2.real-c1.imag*c2.imag;          c.imag=c1.imag*c2.real+c1.real*c2.imag;          return c;      }          //复数相除：(a+bi)/(c+di)=(ac+bd)/(c^2+d^2) +(bc-ad)/(c^2+d^2)i  Complex operator/(Complex &c1,Complex &c2) {          Complex  c;          double d=c2.real*c2.real+c2.imag*c2.imag;      c.real=(c1.real*c2.real+c1.imag*c2.imag)/d;     //此处有危险未排除：除法溢出      c.imag=(c1.imag*c2.real-c1.real*c2.imag)/d;          return c;      }        void display(Complex &c2)    {      cout<<"("<<c2.real<<","<<c2.imag<<"i)"<<endl;  }  int main(){Complex c1(3,4),c2(5,-10),c3,c4;cout<<"c1=";display(c1);cout<<"c2=";display(c2);c3=c1+c2;cout<<"c1+c2=";display(c3);c3=c1-c2;cout<<"c1-c2=";display(c3);c3=c1*c2;cout<<"c1*c2=";display(c3);c3=c1/c2;cout<<"c1/c2=";display(c3);    c4=c1+3.14;cout<<"c1+3.14=";display(c4);c4=3.14+c1;cout<<"3.14+c1=";display(c4);c4=-c1;cout<<"-c1=";display(c4);system("pause");return 0;}

运行结果：

 

经验积累：

1.老师：在声明friend Complex operato+ (Complex &c, const double &d)函数时为什么要在double &d前加const，不加const为什么会出现错误？