C++中采用操作符重载完善复数类

1，复数类应该具有的操作：

1，运算：+，-，*，/；

2，比较：==，!=；

3，赋值：=；

4，求模：modulus；

（5），完善的复数类操作符重载必不可少；

2，利用操作符重载：

1，统一复数与实数的运算方式；

1，Complex operator + (const Complex& c);

2，Complex operator - (const Complex& c);

3，Complex operator * (const Complex& c);

4，Complex operator / (const Complex& c);

2，统一复数域实数的比较方式；

1，bool operator == (const Complex& c);

2，bool operator != (const Complex& c);

3，赋值操作符：

1，Complex& operator = (const Complex& c);

2，特殊在只能将赋值操作符作为成员函数来实现；

4，这些成员函数是普通的函数，只不过使用了 operator 作为函数名的一部分，   因此就成为了操作符重载函数；

3，复数类的实现编程实验：

1，Complex.h 文件：

 #ifndef _COMPLEX_H_
 #define _COMPLEX_H_

 class Complex
 {
     double a;
     double b;
 public:
     Complex(double a = , double b = );
     double getA();
     double getB();
     double getModulus();

     Complex operator + (const Complex& c);
     Complex operator - (const Complex& c);
     Complex operator * (const Complex& c);
     Complex operator / (const Complex& c);

     bool operator == (const Complex& c);
     bool operator != (const Complex& c);

     Complex& operator = (const Complex& c);
 };

 #endif

　2，Complex.cpp 文件：

 #include "Complex.h"
 #include "math.h"

 Complex::Complex(double a, double b)// 默认值只能在函数声明的地方指定；
 {
     this->a = a;
     this->b = b;
 }

 double Complex::getA()
 {
     return a;
 }

 double Complex::getB()
 {
     return b;
 }

 double Complex::getModulus()
 {
     return sqrt(a * a + b * b);
 }

 Complex Complex::operator + (const Complex& c)
 {
     double na = a + c.a;
     double nb = b + c.b;
     Complex ret(na, nb);  // 将实部和虚部指定进去；

     return ret;
 }

 Complex Complex::operator - (const Complex& c)
 {
     double na = a - c.a;
     double nb = b - c.b;
     Complex ret(na, nb);

     return ret;
 }

 Complex Complex::operator * (const Complex& c)
 {
     double na = a * c.a - b * c.b;
     double nb = a * c.b + b * c.a;
     Complex ret(na, nb);

     return ret;
 }

 Complex Complex::operator / (const Complex& c)
 {
     double cm = c.a * c.a + c.b * c.b;
     double na = (a * c.a + b * c.b) / cm;
     double nb = (b * c.a - a * c.b) / cm;
     Complex ret(na, nb);

     return ret;
 }

 bool Complex::operator == (const Complex& c)
 {
     return (a == c.a) && (b == c.b);
 }

 bool Complex::operator != (const Complex& c)
 {
     return !(*this == c);
 }

 Complex& Complex::operator = (const Complex& c)
 {
     if( this != &c )
     {
         a = c.a;
         b = c.b;
     }

     return *this;  // 赋值操作可以连续，所以要返回左操作数；
 }

　3，main.cpp 文件：

 #include <stdio.h>
 #include "Complex.h"

 int main()
 {
     Complex c1(, );
     Complex c2(, );
     Complex c3 = c2 - c1;
     Complex c4 = c1 * c3;
     Complex c5 = c2 / c1;

     printf("c3.a = %f, c3.b = %f\n", c3.getA(), c3.getB());
     printf("c4.a = %f, c4.b = %f\n", c4.getA(), c4.getB());
     printf("c5.a = %f, c5.b = %f\n", c5.getA(), c5.getB());

     Complex c6(, );

     printf("c3 == c6 : %d\n", c3 == c6);
     printf("c3 != c4 : %d\n", c3 != c4);

     (c3 = c2) = c1;

     printf("c1.a = %f, c1.b = %f\n", c1.getA(), c1.getB());
     printf("c2.a = %f, c2.b = %f\n", c2.getA(), c2.getB());
     printf("c3.a = %f, c3.b = %f\n", c3.getA(), c3.getB());

     return ;
 }

　4，输出结果：

 c3.a = 2.000000, c3.b = 4.000000
 c4.a = -6.000000, c4.b = 8.000000
 c5.a = 3.000000, c5.b = 0.000000
 c3 == c6 :
 c3 != c4 :
 c1.a = 1.000000, c1.b = 2.000000
 c2.a = 3.000000, c2.b = 6.000000
 c3.a = 1.000000, c3.b = 2.000000

4，注意事项：

1，C++ 规定赋值操作符（=）只能重载为成员函数；

2，操作符重载不能改变原操作符的优先级；

3，操作符重载不能改变操作数的个数；

4，操作符重载不应改变操作符的原有语义；

5，小结：

1，复数的概念可以通过自定义类实现；

2，复数中的运算操作可以通过操作符重载实现；

3，赋值操作符只能通过成员函数实现；

4，操作符重载的本质为函数定义；

1，定义新的函数扩展已有功能；