Question

Hello guys look to my code I’m trying to make a program which asks you to enter the first value by grams And the second value is kilograms and then convert kilograms to grams by an overloaded + operator but it doesn’t work why

#include <iostream>
using namespace std;
class ADD{
private:
    int Fval;
    int Sval;
public:
    ADD(){
            cout << "WELCOME TO OUR PROGRAM"<<endl<<"PLEASE ENTER THE FIRST VALUE BY GRAMS :";
            cin >> Fval;
            cout << "PLEASE ENTER THE SECOND VALUE BY KILOGRAMS :"; cin >> Sval;
        }
    ADD operator+(ADD& add){
        add.Sval *= 1000;
        return add;
    }
    int plus(){
        return Fval+Sval;
    }
};
int main(){
    ADD a1;
    cout << "THE TOTAL VALUE = " << a1.plus() << " GRAMS";
}

No Effect look to the output

WELCOME TO OUR PROGRAM
PLEASE ENTER THE FIRST VALUE BY GRAMS :2
PLEASE ENTER THE SECOND VALUE BY KILOGRAMS :3
THE TOTAL VALUE = 5 GRAMS

That means the + operator doesn’t multiply 3 by 1000
Why??

Answer 1

That’s because you’re not calling operator +.

You’re calling ADD::plus():

int plus(){
    return Fval+Sval;
}

Fval and Sval are integers, which you’re adding up. It’s as simple as that.

EDIT:

Your code is fishy.

ADD operator+(ADD& add){
    add.Sval *= 1000;
    return add;
}

Multiplication inside operator +? Really? Also, not that you’re modifying the parameter, which you shouldn’t. It’s not intuitive. If you really must do this:

ADD operator+(const ADD& add){
    ADD ret;
    ret.Sval = add.Sval * 1000;
    return ret;
}