重载减法运算符 cpp

Question

I'm a bit new to object oriented programming in c++ and I've been trying to overload subtraction(-) operator in c++ for a Complex class I created. It is working fine except my program is terminating abnormally.
Below is what I've been trying to do:

#include<iostream>
#include<cstdlib>
class Complex{
    //Data-members
private:
    int re, im;

    //methods
public:
    //Constructor
    Complex(){ /*default Constructor*/ }
    Complex(const int& re_, const int& im_):re(re_), im(im_){}
    //Subtraction(-) operator overloading
    Complex operator-(const Complex& op)
    {
        Complex res(this->re - op.re, this->im - op.im);
        return res;
    }
    //get-set methods for re
    int getReal(){ return re; }
    void setReal(const int& re){ this->re = re; }
    //get-set methods for im
    int getImaginary(){ return im; }
    void setImaginary(const int& im){ this->im = im; }
    //Destructor
    ~Complex(){ free(this); }
};

int main()
{
    Complex a(2, 3), b(3, 5);
    Complex d = a - b;
    std::cout<<"d.re = "<<d.getReal()<<" d.im = "<<d.getImaginary()<<"\n";
    return 0;
}

Can anyone please explain the cause of error.

Answer 1

Never ever do free(this) , least of all in the destructor. The memory for the objects will be free'd outside of the destructor, either by the compiler generated code or by the user doing delete or delete[] .

In fact this is the cause of your problem, as the objects created never were allocated with malloc .

The proper solution in this case is to not only remove the free call, but the whole destructor, since it's not needed for this class.