print unsigned int

alaios · 06-03-2005, 08:24 AM

Hi how i can print an unsigned int in c? Is the %2d the correct operand or not for the printf function

trevelluk · 06-03-2005, 08:29 AM

I'd just use %d normally. %2d will force the width of the output to be at least two characters, for example if x = 1:

Code:

/* This will print
1
*/
printf ("%d\n", x);

/* This will print
 1
(note the space at the beginning)
*/

There's many more options than that: see man printf for more information.

alaios · 06-03-2005, 08:48 AM

thx... i have just asked because i was curious to learn if the %d was enough for the double variable

itsme86 · 06-03-2005, 09:22 AM

%u is the correct format specifier for an unsigned int. Otherwise printf() will end up displaying negative numbers, which we all know an unsigned int shouldn't be:

Code:

itsme@itsme:~$ cat toobig.c
#include <stdio.h>

int main(void)
{
  unsigned int num = 0x80000000;

  printf("%%d shows: %d, %%u shows: %u\n", num, num);

  return 0;
}
itsme@itsme:~$ ./toobig
%d shows: -2147483648, %u shows: 2147483648

trevelluk · 06-03-2005, 09:34 AM

Gah, you're right! Sorry, I wasn't paying enough attention there. Need coffee, need coffee....