My console program behaves different on linux and windows

U7Development

Hello!

I have written a very simple menu console program that connects to a mysql db over internet, it works.. just something is not working, since this is a console program it uses std::cin.get() to catch inputs, this happens::

On Windows (works fine)
Program ask user for a name and wait...
user input name
success on saving the name into a std::string
program ask for telephone and wait...
user input telephone
success on saving the telephone into a std::string

On Linux
Program ask user for a name but not wait..
program ask for telephone and wait...

as you can see, there is no way the user can input a name...
i'm flusshing stdin using fflush(stdin) either win and linux, its suppose they must to work the same way..

Any idea?
Thanks so much!

Note my program is a QApplication console program.

Kent-Dorfman

and you included no code for us to see your probable misuse of the cin stream object.

jsulm

This post is deleted!

U7Development

Hm.. may i misunderstood the use of cin object... may be you're right, but Windows is not complaining..
I didn't because code is so long, but i could isolate this:

//Pide al usuario la informacion del nuevo centro
    std::vector<std::string> campos{"Region     :   ", "Nombre     :   ", "Direccion  :   ", "Telefono   :   ", "Email      :   ", "Contrasena :   "};
    for (std::vector<std::string>::iterator it = campos.begin(); it != campos.end(); ++it){

        if (*it == "Region     :   ") continue;
        fflush(stdin);
        std::cout << *it;
        char* t = new char[256];
        std::cin.getline(t, 256);
        centro_actual.push_back(static_cast<std::string>(t));
        delete [] t;
        std::cout << "\n";
    }

//Thanks!!

Here is the full version:
link text

Please, don't tell me that my code is a mess , i know it.. , i wrote it on the fly, the point is that it works on Windows but not on Linux.. :)

I have created a short video explanation:
link text

Thanks again...

JonB

@U7Development said in My console program behaves different on linux and windows:

cin.getline

I don't know, but may I suggest you Google for cin.getline, possibly with "not working". There seems to be quite a few refernces out there saying "it sometimes doesn't work". Various reasons. For one thing, I don't know how well fflush(stdin) plays with cin level, stdin & cin aren't the same thing. I have seen (old) posts like http://www.cplusplus.com/forum/general/1477/. Some suggestion that things like

cin.clear();
cin.sync();
cin.ignore()

might play better? The behaviour difference between Windows vs Linux is presumably down to implementation, even different compilers (with different runtime libraries) might vary?

Kent-Dorfman

This is my OCD influenced rewrite of your code, and it works fine in c++ on Linux. I did change to c++11 constructs because they are more elegant, but I don't really see any problem with your algorithm in the code you supplied, which makes me believe the problem is something else that is influencing the behaviour in a way that makes you think it is a a cin problem, but maybe is not.

    char t[256];
    for (auto it : campos) {
        if (it == "Region     :   ") continue;
        fflush(stdin);
        cout << it;
        cin.getline(t, 256);
        // should really check the error state of cin before adding element
        centro_actual.push_back(t);  // static_cast<string>(t));
        cout << "\n";
    }

U7Development

Ok thanks!.. i will check both answers..