[C++] I'm Stuck: How to directly react on the pressed Tab Key?

Challenges
1

I’m stuck on Stage #(QP2).

I’ve previously read all my commands as one line with getline().
I now use getchar(), but pressing the Tab-Key still does not lead to any direct result. It leads to a result, but I first need to tap enter(\n) after pressing it.

Here is the relevant function in my C++ code:


void CommandReader::readCharacterByCharacter(std::string &currentInput, CommandManager &manager) {
    char c;
    while (true) {
        c = static_cast<char>(getchar());
        if (c == '\n') {
            return; // Input line completed
        } else if (c == '\t') {
            // Autocompletion for Tab Key
            std::vector<std::string> * suggestions = manager.getAllNamesWithPrefix(currentInput);
            if (suggestions && suggestions->size() == 1) {
                 currentInput = suggestions->front();
                 std::cout << "\r" << currentInput << std::flush;  
            }
            delete suggestions;
        } else { 
            currentInput += c;
        }
    }
}

Here is a link to my GitHub Repo.