【C++】 31_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);

编程实验： 复数类的实现

Complex.h

#ifndef _COMPLEX_H_
#define _COMPLEX_H_

class Complex
{
private:
    double a;
    double b;

public:
    Complex(int a = 0, int b = 0);
    int getA();
    int getB();
    int 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

Complex.cpp

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

Complex::Complex(int a, int b)
{
    this->a = a;
    this->b = b;
}

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

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

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

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

// 为了实现循环赋值，将自身引用返回
Complex& Complex::operator = (const Complex& c)
{
    // 若意图自己给自己赋值，则跳过
    if( this != &c )
    {
        a = c.a;
        b = c.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 = c2 + c1;
    Complex c5 = c2 * c1;
    Complex c6 = c2 / c1;
    
    printf("c3.a = %d, c3.b = %d\n", c3.getA(), c3.getB());
    printf("c4.a = %d, c4.b = %d\n", c4.getA(), c4.getB());
    printf("c5.a = %d, c5.b = %d\n", c5.getA(), c5.getB());
    printf("c6.a = %d, c6.b = %d\n", c6.getA(), c6.getB());

    Complex c7(1, 2);
    
    printf("c1 == c7 : %d\n", c1 == c7);
    printf("c2 != c7 : %d\n", c2 != c7);

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

    return 0;
}

输出：
c3.a = 2, c3.b = 4
c4.a = 4, c4.b = 7
c5.a = -9, c5.b = 12
c6.a = 3, c6.b = 0
c1 == c7 : 1
c2 != c7 : 1
c1.a = 1, c1.b = 2
c2.a = 3, c2.b = 6
c3.a = 1, c3.b = 2

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
• 操作符不能改变操作数的个数
• 操作符不应改变操作符的原有语义

小结

• 复数的概念可以通过自定义类实现
• 复数中的运算操作符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

以上内容参考狄泰软件学院系列课程，请大家保护原创！