How to format a number using comma as thousands separator in C?
c, formatting, locale, numbers, printf
Solution
If your printf supports the `'` flag (as required by POSIX 2008 `printf()`), you can probably do it just by setting your locale appropriately. Example:
#include <stdio.h>
#include <locale.h>
int main(void)
{
setlocale(LC_NUMERIC, "");
printf("%'d\n", 1123456789);
return 0;
}
And build & run:
$ ./example
1,123,456,789
Tested on Mac OS X & Linux (Ubuntu 10.10).
Problem
In C, how can I format a large number from e.g. `1123456789` to `1,123,456,789`? I tried using `printf("%'10d\n", 1123456789)`, but that doesn't work. Could you advise anything? The simpler the solution the better.