#include "getopt.h"
#include "string.h"

char* optarg = NULL;
int optind = 1;

int getopt(int argc, char *const argv[], const char *optstring)
{
    if ((optind >= argc) || (argv[optind][0] != '-') || (argv[optind][0] == 0))
    {
        return -1;
    }

    int opt = argv[optind][1];
    const char *p = strchr(optstring, opt);

    if (p == NULL)
    {
        return '?';
    }
    if (p[1] == ':')
    {
        optind++;
        if (optind >= argc)
        {
            return '?';
        }
        optarg = argv[optind];
        optind++;
    }
    return opt;
}