第31课 完善的复数类

完善的复数类
复数类应该具有的操作
运算：+，-，*，/
比较：==，!=
赋值：=
求模：modulus

利用操作符重载
-统一复数与实数的运算方式
-统一复数与实数的比较方式

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);

complex.h

#ifndef COMPLEX_H
#define COMPLEX_H

class Complex
{
 private:
    int a;
    int b;

 public:
    Complex(double a=0, double b=0);
    double GetA();
    double GetB();
    double GetModulus();

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

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

    Complex& operator = (const Complex& p);


};
#endif // COMPLEX_H

complex.cpp

#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& p)
{
   double na = a + p.a;
   double nb = b + p.b;
   Complex ret(na,nb);

   return ret;

}

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

    return ret;

}

Complex Complex::operator *(const Complex& p)
{
   // c1 = a + bi
   // c2 = c + di
   // c1 * c2 = (a*c -b*d) +(b*c+ a*d)

    double na = (a * p.a) - (b * p.b);
    double nb = (b * p.a) + (a * p.b);
    Complex ret(na,nb);

    return ret;
}

Complex Complex::operator /(const Complex& p)
{

    double cm = p.a * p.a + p.b * p.b;
    double na = (a * p.a + b * p.b) / cm;
    double nb = (b * p.a - a * p.b) / cm;
    Complex ret(na,nb);

    return ret;
}

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

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

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

    return *this;
}

main.cpp

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

int main()
{
    Complex c1(1,2);
    Complex c2(3,6);

    Complex c3 = c2 - c1;
    Complex c4 = c1 * c3;
    Complex c5 = c2 / c1;

    printf("c3.a = %f,c3.b = %f
",c3.GetA(),c3.GetB());
    printf("c4.a = %f,c4.b = %f
",c4.GetA(),c4.GetB());
    printf("c5.a = %f,c5.b = %f
",c5.GetA(),c5.GetB());

    Complex c6(2,4);
    printf("c3 == c6: %d
",c3 == c6);
    printf("c3 != c4: %d
",c3 != c4);

    (c3 = c2) = c1;
    printf("c3.a = %f,c3.b = %f
",c3.GetA(),c3.GetB());
    printf("c2.a = %f,c2.b = %f
",c2.GetA(),c2.GetB());
    printf("c1.a = %f,c1.b = %f
",c1.GetA(),c1.GetB());


    return 0;
}

注意事项：
C++规定赋值操作符（=）只能重载为成员函数
操作符重载不能改变原操作符的优先级
操作符重载不能改变操作数的个数
操作符重载不应改变操作符原有语义

小结：
复数的概念可以通过自定义类实现
复数中的运算操作可以通过操作符重载实现
赋值操作符只能通过成员函数实现
操作符重载的本质为函数定义