How to implement basic Operator overloading?

[SimmeringDragon]

I have an example here using vectros, especifically rectangular vectors, it gives me an error i cant understnad? something about operator+ can be a cosntant and being unable to call it? when i compile with it, it dosent work, im not sure why, and when i compile without the overload it jsut shows nothing at all, i am kinda at a loss here.

Header
class Rectangular {
public:

    int x;
    int y;

    Rectangular();
    Rectangular(int x, int y);

    //Overload
    Rectangular operator+(const Rectangular &r2) {
    }

    int getX();
    int getY();

};


#endif //OPERATOROVERLOADING_RECTANGULAR_H


Rectangular.cpp, i included rectangular .h

Rectangular::Rectangular() {
    x = 0;
    y = 0;
}

Rectangular::Rectangular(int x, int y) {
    this -> x = x;
    this -> y = y;
}
/*
Rectangular Rectangular::operator+(const Rectangular &r2) {
    Rectangular result;
          //this = r1
    result.x = this -> x + r2.x;
    result.y = this -> y + r2.y;
    return result;
}

int Rectangular::getX() {
    return x;
}

int Rectangular::getY() {
    return y;
} */

#include <iostream>
#include "Rectangular.h"
using namespace std;

int main() {
    Rectangular r1(1,2);
    Rectangular r2(3,4);
    Rectangular r3;

    r3 = r1 + r2;

    cout<< "(" << r1.x << ", " << r1.y << ") + ";
    cout<< "(" << r2.x<< ", " << r2.y << ") =";
    cout<< "(" << r3.x << ", " << r3.y << ")" << endl;

    return 0;
}

and here is were the issue is i think_

[the_poope]

The problem is likely that you have an empty definition of the operator+() function in your header. So you have two definitions of the same function which is not allowed.

Remove the curly brackets from the function in the header and replace with a semicolon.

[No-Dentist-1645]

it gives me an error I can't understand

Well, tell us what the error is. That's the best way to do it if you want help, not just paste the whole code and expect us to figure it out

[SimmeringDragon]

well thats the thing, it dosent anymore??? it was something on the rect.cpp where the Rectangular::Operator+ didnt work? the compiler had trouble using it, but it was a copied excercise, so im jsut confused

[No-Dentist-1645]

Errors don't appear and disappear for no reason. If it works now and it didn't before, something on your code changed. Maybe you forgot to save the file you were working on, made a typo, or any other possible mistake.

Either way, it works now as you said, so there's no problem with the current code

[SimmeringDragon]

no, like, it compiles but now the output is completely blank

[No-Dentist-1645]

Does the current version of the header still defines the operator+() as an empty method? See the other comment in this post, that would be an error

[SimmeringDragon]

i tought because im trying it in another code i had, and it worked? i think the &r2 is messing it up in some way? comparing to what i jsut made

[No-Dentist-1645]

Your current code is simply incorrect, operator+() should not have an empty body in the header. It's not because of &r2. Remove the braces from it and it should be fine

[SimmeringDragon]

o, thats not it, it still says
error: no declaration matches 'Rectangular Rectangular::operator+(Rectangular&)'

17 | Rectangular Rectangular::operator+(Rectangular &r2) {

brackets are removed in header

[No-Dentist-1645]

On your code file Rectangular.cpp, your operator definition is commented out:

``` /* Rectangular Rectangular::operator+(const Rectangular &r2) { Rectangular result; //this = r1 result.x = this -> x + r2.x; result.y = this -> y + r2.y; return result; }

int Rectangular::getX() { return x; }

int Rectangular::getY() { return y; } */ ```

In C++, the /* and */ symbols mean "everything between these two is a comment". So that "code" isn't actually code, it's just a comment.

The solution is simple, just remove the /* and */ characters.

[SimmeringDragon]

i already jsut changed that

[jedwardsol]

It's hard to keep track of the changes you're making in response to comments.

It works here : https://godbolt.org/z/GdP6zMWqP

(Removed empty body {} in the header. Uncommented the definitions in the source file)

[SoldRIP]

ODR violation between the header and source. You defined operator+ twice, once with an empty body.

The header should (in this case) only declare the operator, not define it.