// // // // // // // // // // // // // // // // // // // // // // // // 
//
//   CS270 Class Example
//
//   Author: Robert Heckendorn
//           University of Idaho
//
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

// this program reads in a command line
// aflg gets set if there is a -a option
// bflg gets set if there is a -b option
// zflg gets set if there is a -z option
//
// a and b options are mutually exclusive
// z prints out when it is discovered
// o option takes a file name and prints out when it is discovered
// extraneous words are considered files are printed out
//
// this program was "borrowed" and extensively modified from the Sun Solaris man
// page for educational purposes only.
//
//  compile:  g++ ouroptTest.cpp
//  test: a.out  ali -a bob -z -z carol -z -o don ella -o frida gill
//
// Robert Heckendorn  Mar 6, 2006
//
int main(int argc, char **argv)
{

    // // // // // // // // // // // // //
    // begin of arg processing
    extern char *optarg; // if takes a value then it is returned here
    extern int optind;   // index into argv
    extern int optopt;   // invalid character on error
    extern int opterr;   // set to zero to force getopt to be silent on errors
//    extern int optreset;  

    int c;
    bool aflg, nflg, oflg, zflg, errflg;
    char *ofile;
    int num;

    aflg = nflg = oflg = zflg = errflg = false;
    ofile = NULL;
    num = 0;
    opterr = 0;

    // hunt for a string of options
    while ((c = getopt(argc, argv, "an:o:z")) != EOF)
        switch (c) {
        case  'a':               // set flag
            aflg = true;
            break;
        case  'n':               // take an integer argument
            char *endptr;
	    int tmpnum;

            nflg = true;
            tmpnum = strtol(optarg, &endptr, 10);
            if (*endptr!='\0') {
                fprintf(stderr, "ERROR(%s): number on -n option: %s is not a legal integer.\n", argv[0], optarg);
            }
	    else {
                num = tmpnum;
	    }
            break;
        case        'o':      // take a file (use once)
            if (oflg) {
                fprintf(stderr, "ERROR(%s): -o option can be used only once.  First one is used.\n", argv[0]);
            }
            else {
                oflg = true;
                ofile = strdup(optarg);
            }
            break;
        case        'z':     // set flag
            zflg = 1;
            break;
        case        ':':  // missing argument case
            fprintf(stderr, "ERROR(%s): option -%c requires an option\n", argv[0], optopt);
            errflg = 1;
            break;

        case        '?':  // bad option case
        default:
            fprintf(stderr, "ERROR(%s): option -%c is not an option\n", argv[0], optopt);
            errflg = 1;
        }

    // report any errors or usage request
    if (errflg) {
        fprintf(stderr, "usage: %s [-a] [-z] [-o <filename>] files...\n", argv[0]);
// do you want to continue?        exit(2);
    }

    // pick off a nonoptions as if they were files
    for (; optind < argc; optind++) {
        (void)printf("file: %s\n", argv[optind]);
    }

    // end of arg processing
    // // // // // // // // // // // // //

    // what did we find?
    if (aflg) printf("option 'a' was found\n");
    if (nflg) printf("option 'n' was found with number: %d\n", num);
    if (oflg) printf("option 'o' was found with file: %s\n", ofile);
    if (zflg) printf("option 'z' was found\n");

    return 0;
}