Overloading subtraction operator cpp

-5

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.

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

asked Nov 14 '18 at 11:52

user9999486

What free(this); is supposed to do? It's unnecessary and causes the error.

– HolyBlackCat
Nov 14 '18 at 11:55

Also, why pass const int& instead of a plain int?

– HolyBlackCat
Nov 14 '18 at 11:56

1

Remove the free(this) from the destructor. Calling free() with an argument that was not returned by malloc() (or related functions, like calloc() or realloc()) gives undefined behaviour. There is nothing in your code returned by malloc(), and doesn't need to be.

– Peter
Nov 14 '18 at 11:57

See also rule of three here

– anatolyg
Nov 14 '18 at 11:58

1

@anatolyg - rule of zero is more applicable here. The class doesn't explicitly manage any resource, compiler-supplied default implementations of copy constructor, assignment operator, and destructor are fine.

– Peter
Nov 14 '18 at 12:00

|
show 2 more comments

-5

#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.

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

asked Nov 14 '18 at 11:52

user9999486

What free(this); is supposed to do? It's unnecessary and causes the error.

– HolyBlackCat
Nov 14 '18 at 11:55

Also, why pass const int& instead of a plain int?

– HolyBlackCat
Nov 14 '18 at 11:56

1

Remove the free(this) from the destructor. Calling free() with an argument that was not returned by malloc() (or related functions, like calloc() or realloc()) gives undefined behaviour. There is nothing in your code returned by malloc(), and doesn't need to be.

– Peter
Nov 14 '18 at 11:57

See also rule of three here

– anatolyg
Nov 14 '18 at 11:58

1

@anatolyg - rule of zero is more applicable here. The class doesn't explicitly manage any resource, compiler-supplied default implementations of copy constructor, assignment operator, and destructor are fine.

– Peter
Nov 14 '18 at 12:00

|
show 2 more comments

-5

#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.

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

asked Nov 14 '18 at 11:52

user9999486

#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.

c++

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

asked Nov 14 '18 at 11:52

user9999486

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

asked Nov 14 '18 at 11:52

user9999486

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

edited Nov 14 '18 at 13:09

Ted Lyngmo

2,5652317

asked Nov 14 '18 at 11:52

user9999486

asked Nov 14 '18 at 11:52

user9999486

asked Nov 14 '18 at 11:52

user9999486

What free(this); is supposed to do? It's unnecessary and causes the error.

– HolyBlackCat
Nov 14 '18 at 11:55

Also, why pass const int& instead of a plain int?

– HolyBlackCat
Nov 14 '18 at 11:56

1

Remove the free(this) from the destructor. Calling free() with an argument that was not returned by malloc() (or related functions, like calloc() or realloc()) gives undefined behaviour. There is nothing in your code returned by malloc(), and doesn't need to be.

– Peter
Nov 14 '18 at 11:57

See also rule of three here

– anatolyg
Nov 14 '18 at 11:58

1

@anatolyg - rule of zero is more applicable here. The class doesn't explicitly manage any resource, compiler-supplied default implementations of copy constructor, assignment operator, and destructor are fine.

– Peter
Nov 14 '18 at 12:00

|
show 2 more comments

What free(this); is supposed to do? It's unnecessary and causes the error.

– HolyBlackCat
Nov 14 '18 at 11:55

Also, why pass const int& instead of a plain int?

– HolyBlackCat
Nov 14 '18 at 11:56

1

Remove the free(this) from the destructor. Calling free() with an argument that was not returned by malloc() (or related functions, like calloc() or realloc()) gives undefined behaviour. There is nothing in your code returned by malloc(), and doesn't need to be.

– Peter
Nov 14 '18 at 11:57

See also rule of three here

– anatolyg
Nov 14 '18 at 11:58

1

@anatolyg - rule of zero is more applicable here. The class doesn't explicitly manage any resource, compiler-supplied default implementations of copy constructor, assignment operator, and destructor are fine.

– Peter
Nov 14 '18 at 12:00

What free(this); is supposed to do? It's unnecessary and causes the error.

– HolyBlackCat
Nov 14 '18 at 11:55

Also, why pass const int& instead of a plain int?

– HolyBlackCat
Nov 14 '18 at 11:56

Remove the free(this) from the destructor. Calling free() with an argument that was not returned by malloc() (or related functions, like calloc() or realloc()) gives undefined behaviour. There is nothing in your code returned by malloc(), and doesn't need to be.

– Peter
Nov 14 '18 at 11:57

See also rule of three here

– anatolyg
Nov 14 '18 at 11:58

@anatolyg - rule of zero is more applicable here. The class doesn't explicitly manage any resource, compiler-supplied default implementations of copy constructor, assignment operator, and destructor are fine.

– Peter
Nov 14 '18 at 12:00

|
show 2 more comments

1 Answer
1

active

oldest

votes

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.

edited Nov 14 '18 at 12:18

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

using delete is also terminating the program abnormally.

– user9999486
Nov 14 '18 at 11:59

@user9999486 delete must match a new, a delete must match a new. Nowhere in your code do you use new, so there shouldn't be any delete. As I said, it will be done automatically by the compiler since it is the compiler that allocates the objects.

– Some programmer dude
Nov 14 '18 at 12:05

so there is no need for the destructor. Right ???

– user9999486
Nov 14 '18 at 12:08

@user9999486 No, not in this example anyway.

– Some programmer dude
Nov 14 '18 at 12:08

how do we know that we need to add an explicit destructor in a class

– user9999486
Nov 14 '18 at 12:09

|
show 2 more comments

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1 Answer
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active

oldest

votes

1 Answer
1

active

oldest

votes

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.

edited Nov 14 '18 at 12:18

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

using delete is also terminating the program abnormally.

– user9999486
Nov 14 '18 at 11:59

@user9999486 delete must match a new, a delete must match a new. Nowhere in your code do you use new, so there shouldn't be any delete. As I said, it will be done automatically by the compiler since it is the compiler that allocates the objects.

– Some programmer dude
Nov 14 '18 at 12:05

so there is no need for the destructor. Right ???

– user9999486
Nov 14 '18 at 12:08

@user9999486 No, not in this example anyway.

– Some programmer dude
Nov 14 '18 at 12:08

how do we know that we need to add an explicit destructor in a class

– user9999486
Nov 14 '18 at 12:09

|
show 2 more comments

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.

edited Nov 14 '18 at 12:18

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

using delete is also terminating the program abnormally.

– user9999486
Nov 14 '18 at 11:59

@user9999486 delete must match a new, a delete must match a new. Nowhere in your code do you use new, so there shouldn't be any delete. As I said, it will be done automatically by the compiler since it is the compiler that allocates the objects.

– Some programmer dude
Nov 14 '18 at 12:05

so there is no need for the destructor. Right ???

– user9999486
Nov 14 '18 at 12:08

@user9999486 No, not in this example anyway.

– Some programmer dude
Nov 14 '18 at 12:08

how do we know that we need to add an explicit destructor in a class

– user9999486
Nov 14 '18 at 12:09

|
show 2 more comments

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.

edited Nov 14 '18 at 12:18

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

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.

edited Nov 14 '18 at 12:18

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

edited Nov 14 '18 at 12:18

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

answered Nov 14 '18 at 11:55

Some programmer dude

299k25253416

using delete is also terminating the program abnormally.

– user9999486
Nov 14 '18 at 11:59

@user9999486 delete must match a new, a delete must match a new. Nowhere in your code do you use new, so there shouldn't be any delete. As I said, it will be done automatically by the compiler since it is the compiler that allocates the objects.

– Some programmer dude
Nov 14 '18 at 12:05

so there is no need for the destructor. Right ???

– user9999486
Nov 14 '18 at 12:08

@user9999486 No, not in this example anyway.

– Some programmer dude
Nov 14 '18 at 12:08

how do we know that we need to add an explicit destructor in a class

– user9999486
Nov 14 '18 at 12:09

|
show 2 more comments

using delete is also terminating the program abnormally.

– user9999486
Nov 14 '18 at 11:59

@user9999486 delete must match a new, a delete must match a new. Nowhere in your code do you use new, so there shouldn't be any delete. As I said, it will be done automatically by the compiler since it is the compiler that allocates the objects.

– Some programmer dude
Nov 14 '18 at 12:05

so there is no need for the destructor. Right ???

– user9999486
Nov 14 '18 at 12:08

@user9999486 No, not in this example anyway.

– Some programmer dude
Nov 14 '18 at 12:08

how do we know that we need to add an explicit destructor in a class

– user9999486
Nov 14 '18 at 12:09

using delete is also terminating the program abnormally.

– user9999486
Nov 14 '18 at 11:59

@user9999486 delete must match a new, a delete must match a new. Nowhere in your code do you use new, so there shouldn't be any delete. As I said, it will be done automatically by the compiler since it is the compiler that allocates the objects.

– Some programmer dude
Nov 14 '18 at 12:05

so there is no need for the destructor. Right ???

– user9999486
Nov 14 '18 at 12:08

@user9999486 No, not in this example anyway.

– Some programmer dude
Nov 14 '18 at 12:08

how do we know that we need to add an explicit destructor in a class

– user9999486
Nov 14 '18 at 12:09

|
show 2 more comments

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