Is there a way to get text as soon as possible without waiting for a newline?

Question

I\'m using C. I wrote a very simpe program which prints back the input, using getchar() and putchar() or printf(). Is there any way to make it so as soon as the user types one k

Answer 1

If you're using Visual Studio, you can use getch().

Answer 2

On Linux you can take over the terminal:

#include <stdio.h>
#include <ctype.h>
#include <termios.h>

system("stty raw"); /* raw output to terminal, direct feedback */
system("clear"); /* clear screen */

printf("Press a key");
answer = getchar();

system("stty cooked"); /* revert back*/

Answer 3

In this simple case, the other answers should suit you fine.

The general solution is to disable line buffering. This depends on the particular console; the following example is Windows-only (untested):

#include <windows.h>

int main() {
    HANDLE hConsole = GetStdHandle(STD_INPUT_HANDLE);
    DWORD mode;
    GetConsoleMode(hConsole, &mode);
    SetConsoleMode(hConsole, mode & ~ENABLE_LINE_INPUT);
    // ...
}

I assume that the standard C library functions are implemented in terms of ReadConsole and friends; if not, this might not even work. (I'm currently on Linux, so I cannot test this.)

Answer 4

if you are using Visual Studio, there is a library called conio (#include <conio.h>) which defines a kbhit() function and getch().

otherwise, on Windows, there is still the possibility of using functions from the Windows SDK (ReadConsoleInput() and the like), but that would require a little bit more code (although, once done and if done properly, it can be reused any time you want)