Overloading operator ==

Hi,
to practice overloading operators I'm building a Fractions class.
I have a question about comparison operators. In a tutorial, the overloaded == returned an int (1 or 0) - wouldn't it make more sense to return a bool (true or false)? Would it matter - I guess overloading these operators is important if you want to use the sort algorithm on them and such?

This is what I have to compare fractions. Is it OK?

Code:

class Fraction
{
    public:
        Fraction(int up = 0, int low = 1):upper(up), lower(low) {}
        ~Fraction() {}
        //....
        bool operator== (const Fraction f)
        {
            if (this->upper * f.lower == this->lower*f.upper)
                return true;
            else
                return false;
        }
    private:
        int upper, lower;
};

The only thing I have to say, is pass a const reference to Fraction f, so that you don't have to copy Fraction f everytime you use operator ==().

Code:

if (this->upper * f.lower == this->lower*f.upper)
    return true;
else
    return false;

Just a nit, but this can be simplified a bit to this:

Code:

return this->upper * f.lower == this->lower * f.upper;

Thanks, both are excellent suggestions! Never thought of that...

>> wouldn't it make more sense to return a bool (true or false)?
Yes. You should return a bool.

>> This is what I have to compare fractions. Is it OK?
If you make it a member function, you should make the function const as well as making the parameter a const reference as citizen mentioned. However, in this case it should not be a member. It should be a non-member function:

Code:

bool operator==(const Fraction& f1, const Fraction& f2);

You would have to make it a friend in this case, since you use the private upper and lower members, but that is ok.