[英]Overloading * operator for complex numbers (C++)
因此,我被要求重載運算符以實現復數的基本算法。 我已經+,-和=工作了,但是即使我認為我有正確的邏輯,我似乎也無法工作。
我的代碼有什么問題?
#ifndef COMPLEX_HPP
#define COMPLEX_HPP
#include <string>
class Complex
{
public:
Complex(double = 0.0, double = 0.0); // default constructor
Complex add(const Complex&) const; // function add
Complex subtract(const Complex&) const; // function subtract
Complex multiply(const Complex&) const; // function multiply
std::string toString() const; // return string representation
void setComplexNumber(double, double); // set complex number
void operator=(const Complex& obj)
{
(*this).realPart = obj.realPart;
(*this).imaginaryPart = obj.imaginaryPart;
}
Complex operator+(const Complex& obj)
{
Complex tmp_obj = *this;
tmp_obj.realPart = tmp_obj.realPart + obj.realPart;
tmp_obj.imaginaryPart = tmp_obj.imaginaryPart + obj.imaginaryPart;
return tmp_obj;
}
Complex operator-(const Complex& obj)
{
Complex tmp_obj = *this;
tmp_obj.realPart = tmp_obj.realPart - obj.realPart;
tmp_obj.imaginaryPart = tmp_obj.imaginaryPart - obj.imaginaryPart;
return tmp_obj;
}
Complex operator*(const Complex&obj)
{
Complex tmpObj = *this;
tmpObj.realPart = (tmpObj.realPart * obj.realPart) - (tmpObj.imaginaryPart * obj.imaginaryPart);
tmpObj.imaginaryPart = (tmpObj.realPart * obj.imaginaryPart) + (tmpObj.imaginaryPart * obj.realPart);
return tmpObj;
}
private:
double realPart;
double imaginaryPart;
};
一旦開始覆蓋tmpObj
(特別是tmpObj.realPart
),您將丟失原始值。 所以不要從tmpObj
讀取,而是從*this
讀取:
tmpObj.realPart = realPart * obj.realPart - imaginaryPart * obj.imaginaryPart;
// ^^^^^^^^ ^^^^^^^^^^^^^
tmpObj.imaginaryPart = realPart * obj.imaginaryPart + imaginaryPart * obj.realPart;
// ^^^^^^^^ ^^^^^^^^^^^^^
本質上,您對operator*()
是。
Complex operator*(const Complex&obj)
{
Complex tmpObj = *this;
tmpObj.realPart = (tmpObj.realPart * obj.realPart) - tmpObj.imaginaryPart * obj.imaginaryPart);
tmpObj.imaginaryPart = (tmpObj.realPart * obj.imaginaryPart) + (tmpObj.imaginaryPart * obj.realPart);
return tmpObj;
}
問題在於,第一條語句修改了tmpObj.realPart
,而第二條語句繼續進行,就好像tmpObj.realPart
。
解決方法很簡單:不要在分配的右側使用tmpObj
。
Complex operator*(const Complex&obj)
{
Complex tmpObj; // your default constructor initialises to (0.0,0.0)
tmpObj.realPart = (realPart * obj.realPart) - (imaginaryPart * obj.imaginaryPart);
tmpObj.imaginaryPart = (realPart * obj.imaginaryPart) + (imaginaryPart * obj.realPart);
return tmpObj;
}
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