Qt Creator inner terminal autoinputs 0 when there is cin stream

JacobNovitsky

How to solve it?

#include <iostream>
#include <limits>  // for std::numeric_limits

int main() {
    std::string key;

    std::cout << "Enter a key: ";
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // Clear input buffer
    std::getline(std::cin, key);

    // Output the first character's ASCII value
    if (!key.empty()) {
        std::cout << "Key: " << int(key[0]) << std::endl;
    } else {
        std::cout << "Key is empty." << std::endl;
    }

    return 0;
}

if change to gnome-terminal then back it does the trick

jsulm

@JacobNovitsky said in Qt Creator inner terminal autoinputs 0 when there is cin stream:

std::cin.ignore(std::numeric_limitsstd::streamsize::max(), '\n');

This line is the problem - first enter press is ignored.
Why don't you use std::cin.clear(); instead?

JonB

@jsulm
It comes from https://en.cppreference.com/w/cpp/string/basic_string/getline. I thought that line prior to the getline() just flushes anything which may be sitting in the buffer from before, does not affect the following getline()?

jsulm

@JonB For me it does affect getline - I enter something, press enter, nothing happens, second enter then works.

JonB

@jsulm
I think then that careful reading of that item must mean you are only supposed to use it if you know there is something already sitting there left over from before and you want to flush it. It must mean ignore everything up to the next newline in the buffer, whenever that is. The OP should certainly try removing it. I don't know what the OP's "autoinputs 0" means, nor why it apparently has different effect in same situation from gnome-terminal.