#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char const *argv[])
{
    if (argc != 3 && argc != 4) {
        fprintf(stderr, "%s\n", "wrong arguments");
        return 1;
    }
    if (argc == 3) {
        fprintf(stderr, "%s\n", "with append");
        int fd = open(argv[1], O_WRONLY | O_CREAT | O_APPEND);
        if (fd == -1) {
            fprintf(stderr, "%s\n", "error while opening");
            return 1;
        }
        int num_bytes = atoi(argv[2]);
        for (int i = 0; i < num_bytes; ++i) {
            write(fd, "0", 1);
        }
        close(fd);
    } else {
        fprintf(stderr, "%s\n", "without append");
        int fd = open(argv[1], O_WRONLY | O_CREAT);
        int num_bytes = atoi(argv[2]);
        if (fd == -1) {
            fprintf(stderr, "%s\n", "error while opening");
            return 1;
        }
        for (int i = 0; i < num_bytes; ++i) {
            lseek(fd, 0, SEEK_END);
            write(fd, "0", 1);
        }
        close(fd);
    }
    return 0;
}