/*----------------------------------------------------------------------
 | This program is used to show how integer, double, and string
 | parameters can be retrieved from the command-line using
 | getopt()
 | 
 | Usage: %s [-i int] [-d double] [-f filename]
 |----------------------------------------------------------------------*/

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#define MAX_LINE 120

void parseCommandLine(int argc, char *argv[], int *myInt, double *myDouble, 
                      char **myString);
void printUsage(char *argv[]);

/*----------------------------------------------------------------------
 |
 |----------------------------------------------------------------------*/
int main(int argc, char *argv[])
{
    int    anInt    = -1;
    double aDouble  = -1.0;
    char   filename[MAX_LINE];


    sprintf(filename, "initialized");
    parseCommandLine(argc, argv, &anInt, &aDouble, (char **) &filename);

    printf("Current values: \n\n");
    printf("\tanInt   = %d\n", anInt);
    printf("\taDouble = %.3f\n", aDouble);
    printf("\tFile    = [%s]\n]n", filename);

    return  0;
}


/*----------------------------------------------------------------------
 | Output:
 |    1. myInt: optional integer argument
 |    2. myDouble: optional double (floating point) argument
 |    3. myString: optional pathname argument
 |----------------------------------------------------------------------*/
void parseCommandLine(int argc, char *argv[], int *myInt, double *myDouble, 
                      char **myString)

{
    extern char *optarg;
    int c;


    while ((c = getopt(argc, argv, "i:d:f:")) != -1) 
    {
        switch (c) 
        {
            case 'i': *myInt = atoi(optarg);
                      break;

            case 'd': *myDouble = atof(optarg);
                      break;

            case 'f': strncpy( (char *) myString, optarg, MAX_LINE);
                      break;

            default : printUsage(argv);
                      exit(1);
        }
    }
}


/*----------------------------------------------------------------------
 | printUsage: output the USAGE for using this application.
 |----------------------------------------------------------------------*/
void printUsage(char *argv[])
{
    printf("Usage: %s [-i int] [-d double] [-f filename]\n", argv[0]);
    printf("\n");
    printf("This program is used to show how integer, double, and string\n");
    printf("parameters can be retrieved from the command-line using getopt()\n");
    fflush(stdout);
}