Помощ със задача с функция на C

[MaGuSs]

...

Авторa/ката е писала "C", а не "C++"

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

static void
decimal_to_binary (int number){
    char * digits;
    int n_digits,i,copy;
    copy = number;
    n_digits = 0;
    while (copy) {
        n_digits++;
        copy /= 2;
    }
    digits = malloc (n_digits);
    if (! digits) {
        fprintf (stderr, "No more memory.\n");
        exit (EXIT_FAILURE);
    }
    i = 0;
    copy = number;
    while (copy) {
        digits[i] = copy % 2;
        copy /= 2;
        i++;
    }
    printf ("Decimal %d = binary ", number);
    for (i = n_digits - 1; i >= 0; i--) {
        printf ("%d", digits[i]);
    }
    printf ("\n");
    free (digits);
}
int main (int argc, char ** argv)
{
    int i;
    const int base = 10;
    for (i = 1; i < argc; i++) {

        char * arg;
        char * end;
        int number;
        arg = argv[i];
        number = strtol (arg, & end, base);
        if (arg != end) {
            decimal_to_binary (number);
        }
    }
    return 0;
}