#include "fmt.h"unsigned int fmt_ulong(s,u) register char *s; register unsigned long u;{  register unsigned int len; register unsigned long q;  len = 1; q = u;  while (q > 9) { ++len; q /= 10; }  if (s) {    s += len;    do { *--s = '0' + (u % 10); u /= 10; } while(u); /* handles u == 0 */  }  return len;}