31课.完善的复数类

Posted 2020-11-23 huangdengtao

利用操作符重载的练习

注意事项：
1.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符的个数
4.操作符重载不应改变操作符的原有语义（3，4说明操作符重载只是对原有操作符功能的扩展，但是不能改变其本质的含义。比如：+只能是二目运算符的加法。不能是三目，也不能是减法）

练习：完善复数符+，-，*，/，==，！，=；
头文件：

#ifndef _COMPLEX_H_
#define _COMPLEX_H_

class Complex
{
    double a;
    double b;
public:
    Complex(double a = 0, double b = 0);
    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

.cpp文件

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

Complex::Complex(double a, double b)        
{
    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;           //成员函数可以直接使用成员变量
    double nb = b + c.b;
    Complex ret(na, nb);
    
    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);        //这里引用了上面的==
}
    
Complex& Complex::operator = (const Complex& c)
{
    if( this != &c )        //如果左右操作数不是同一个对象，再进行赋值
    {
        a = c.a;
        b = c.b;
    }
    
    return *this;            //赋值操作是可以是连续的返回（对象的引用），并且赋值操作返回值为做操作数（返回*this）。
}