Random IP address generator implemented in the one language to rule them all

C_rIP.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <stdint.h>
#include <string.h>

int main(int argc, char **argv)
{
    FILE    *file_out;
    char     string_ip_count[4096];
    char    *string_end;
    uint64_t ip_count;

    srand(time(0));

    file_out = fopen("C_rIP_out.txt", "wb");

    if (file_out == NULL) {
        return 1;
    }

    setvbuf(file_out, NULL, _IOFBF, 65536);

    fputs("Number of IP addresses: ", stdout);

    if (argc < 2) {
        fgets(string_ip_count, 4096, stdin);  // NOTE: Lovely memory leak right here
    } else if (strlen(argv[1]) < 4096) {
        strcpy(string_ip_count, argv[1]);
    } else {
        memcpy(string_ip_count, argv[1], 4095);

        string_ip_count[4095] = 0x00;
    }

    ip_count = strtoull(string_ip_count, &string_end, 10);  // TODO: Validate the user input if you don't want your CPU to catch fire

    for (int i = 0; i < ip_count; i++) {
        fprintf(file_out, "%d.%d.%d.%d\n",
            rand() % 0xFF,
            rand() % 0xFF,
            rand() % 0xFF,
            rand() % 0xFF);
    }

    fclose(file_out);

    return 0;
}