how to get a character from stdin without waiting for user to put it? [duplicate]

Answer 1

There's an answer to this in the comp.lang.c FAQ. See question 19.1, "How can I read a single character from the keyboard without waiting for the RETURN key? How can I stop characters from being echoed on the screen as they're typed?".

It's a bit long to post here.

Answer 2

ncurses has the capability to do this through it's own getch() function. See this page

#include <curses.h>

int main(void) {
  initscr();
  timeout(-1);
  int c = getch();
  endwin();
  printf ("%d %c\n", c, c);
  return 0;
}

Answer 3

Since you're using ncurses, you start by calling cbreak to turn off line buffering. Then you'll call nodelay to tell it not to wait before returning -- getch will always return immediately. When it does, you'll check whether a key was pressed, and if so what key that was (and react appropriately).