Taking input without disturbing the program execution in c

Question

I want to take input in a loop without stopping its execution i.e.

`

   #include<stdio.h>
   #include<stdlib.h>
   #include<conio.h>
   int main()
   {
    char c;
      while(1)
      {

        if((c=getch())=='y')
                printf("yes\n") ;

        printf("no\n") ;
     }
      return 0;
   }

Now i want that "no" should be printed infinitely regardless of input and if i press y then yes should be printed.And then continuing from no again. Is this possible, any IDEA!

getch() will block on a read. To do what you want, try doing a non-blocking read on STDIN_FILENO. — William Pursell, Dec 10 '14 at 19:20
Threading---- Print `no` in one thread and the `yes` in another — Bhargav Rao, Dec 10 '14 at 19:20
@BhargavRao: Nonsense. That's not even a reasonable suggestion. — Ken White, Dec 10 '14 at 19:23
You could use `select()` or `poll()` in conjunction with `getch()` to ensure that it will be non-blocking. — Gillespie, Dec 10 '14 at 19:23
@KenWhite Had tried that once and it had worked. But if it is crap, then even I'm enthusiastic about the answer. — Bhargav Rao, Dec 10 '14 at 19:24
@BhargavRao: 1) This is C, where there isn't much threading support. 2) A thread isn't even a viable suggestion for a solution, as it has nothing to do with anything a thread would solve. — Ken White, Dec 10 '14 at 19:26
possible duplicate of [C non-blocking keyboard input](http://stackoverflow.com/questions/448944/c-non-blocking-keyboard-input) — Lee Daniel Crocker, Dec 10 '14 at 19:33

score 0 · Accepted Answer · answered Dec 10 '14 at 19:52

Since this appears to be on Windows and you're already using the old conio functions, you could double down with _kbhit():

#include<stdio.h>
#include<stdlib.h>
#include<conio.h>

int main()
{
  while(1)
  {
    if(_kbhit() && getch() == 'y')
      printf("yes\n");

    printf("no\n") ;
  }
  return 0;
}

_kbhit() "checks the console for a recent keystroke," according to the documentation. What that means is that if _kbhit() is true, getch() will be able to get a character immediately and not block.

Taking input without disturbing the program execution in c

1 Answers1