Problems using overloaded extraction operator in C++

Question

I have created a Time class with the following overloading of the >> operator (they use HH:MM:SS format):

inline std::istream& operator>>(std::istream& in, Hora& h) { //Our teacher says we have to implement it with inline and not with friend
    std::string aux;
    in >> aux;
    std::string aux_hora = aux.substr(0, 1);
    std::string aux_min = aux.substr(3, 4);
    std::string aux_seg = aux.substr(6, 7);
    h = Hora(std::stoi(aux_hora), std::stoi(aux_min), std::stoi(aux_seg));
    return in;
}

My problem is, how do I have to use the cin operator then in the main.cpp ? I have tried writing this but the compiler says that I'm using uninitialized variables:

int hora, min, seg;
Hora h(hora, min, seg);
std::cin >> h;

If you need something else, please tell me. Thank you very much.

Answer 1

At first glance, it looks like your problem is in the test code, not the overloaded operator. This code:

int hora, min, seg;
Hora h(hora, min, seg);

...creates an Hora object, initialized from the current values of hora , min , and seg . But those haven't been initialized...

I'd try something like:

int hora=0, min=0, seg=0;
Hora h(hora, min, seg);

...and see if that fixes the warning. If not, it looks to me like the warning is probably in code you haven't shown us.

Obligatory aside: when/if you want to do something like this in real code (not just an assignment) you probably want to use std::get_time instead.