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

int main(int argc, char **argv) {
  if (argc < 2) {
    return -1;
  }

  int in = atoi(argv[1]);

  if (in == 0) {
    printf("0\n");
    return 0;
  }

  int negative = in < 0 ? 1 : 0;
  printf("negative: %d\n", negative);

  int digits = 0;

  int tmp = in;

  while (tmp != 0) {
    tmp /= 10;
    digits++;
  }
  printf("digits: %d\n", digits);

  char out[digits + negative + 1];
  out[0] = negative ? '-' : 0;
  out[sizeof(out)-1] = '\0';

  tmp = in;
  int i;

  for (i = negative ? digits : digits-1 ; i >= negative ? 1 : 0; i--) {
    out[i] = negative ? (tmp % 10) * -1 + 48 : (tmp % 10) + 48;
    tmp /= 10;
  }

  printf("%s\n", out);

  return 0;
}