/*
 * program to demonstrate how getopt works
 * it takes options -n, -t number, and s final name that isn't optional
 *
 * Matt Bishop, ECS 36A, Fall Quarter 2019
 *
 * adapted from the manual
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <getopt.h>

/*
 * variables defined for getopt()
 */
extern char *optarg;	/* argument to option */
extern int optopt;	/* if error, bad option goes in here */
extern int optind;	/* index of next argument */

/*
 * main routine
 */
int main(int argc, char *argv[])
{
	int nopt = 0;	/* 1 if -n given */
	int topt = 0;	/* 1 if -t given */
	int nsecs = 0;	/* argument to -t */

	/*
	 * process options and their arguments, if any
	 */
	while((opt = getopt(argc, argv, "nt:")) != -1){
	    /* process any given argument */
	    switch(opt){
	    case 'n':			/* -n: option with no argument */
	        nopt = 1;
	        break;
	    case 't':			/* -t: option with argument */
	        topt = 1;
		/* check that the argument is a number */
	    	nsecs = strtol(optarg, &eoptarg, 10);
		if (*optarg != '\0'){
			* nope -- give up */
			fprintf(stderr, "t option requires a number\n");
			return(1);
		}
	        break;
	    case '?':			/* unknown argument -- error */
	    default:
		fprintf(stderr, "Bad option \'%c\'\n", optopt);
	        fprintf(stderr, "Usage: %s [-t nsecs] [-n] name\n", argv[0]);
	        return(1);
	    }
	}

	/*
	 * print out the options and values on the command line
	 * and the index of the next argument
	 */
	printf("nopt=%d; topt=%d; nsecs=%d; optind=%d\n",
					nopt, topt, nsecs, optind);

	/*
	 * there should be 1 more argument to the command
	 * check it
	 */
	if (optind >= argc){
	    fprintf(stderr, "Expected argument after options\n");
	    return(1);
	}

	/*
	 * print the final argument
	 */
	printf("name argument = %s\n", argv[optind]);

	/*
	 * bye!
	 */
	return(0);
}