Question

I have this small C program (play.c):

#include <stdio.h>

main() {
  int t;
  for (t=0; t<8000; t++) {
    printf ("%c", t%256);
  }
}

when I redirect it’s output (in Linux):

./play > /dev/audio

it plays a sound as I expect. But if I format the output in printf as int (%d) instead of char, I get a different sound (and a wrong one, as far as my ears are telling me).

Why does that happen? Aren’t the same numbers are sent to the audio device?

Answer 1

No, as man printf would tell you, or a simple diff on the output redirected into two files. ‘%c’ prints the unsigned char part (the first 8 bits) as one character, and ‘%d’ the whole number in base-10 digit representation.