Command line input

This is a discussion on Command line input within the C Programming forums, part of the General Programming Boards category; Hi, I don't know how to fix this: input: prog -a-a output: a prog: unknown option -- - a Code: ...

  1. #1
    Registered User
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    Jun 2006
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    130

    Command line input

    Hi,
    I don't know how to fix this:

    input: prog -a-a
    output:
    a
    prog: unknown option -- -
    a

    Code:
    while (( c = getopt (argc, argv, "ab")) != -1)
     {
        switch (c)
        {
           case 'a':
           printf ("a...\n");
           break;
    
           case 'b':
           printf("b...\n");
           break;
    
           case '?':
           default:
           usage();
           break;
        }
     }

  2. #2
    Eager young mind
    Join Date
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    342
    Dont u think there's something wrong with using argc and argv that way...
    main() takes in two arguments.One is an integer that specifies the number of arguments at the prompt
    and the other argument is a char *argv[] in which each element of the array is a pointer to a different char array....

  3. #3
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    Quote Originally Posted by kris.c
    Dont u think there's something wrong with using argc and argv that way...
    main() takes in two arguments.One is an integer that specifies the number of arguments at the prompt
    and the other argument is a char *argv[] in which each element of the array is a pointer to a different char array....
    so...

  4. #4
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    I think that the usage of getopt() is correct ...

  5. #5
    Eager young mind
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    yeah, but u r giving

    prog -a-a.. at the prompt,arent u?? and if u r just specifying the argument what is that " - " doing there?

  6. #6
    Eager young mind
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    ok , I understand ur problem, this is what u might have intended to do :

    prog -a -a

    this gives u the reqd o/p..
    Last edited by kris.c; 07-20-2006 at 05:37 AM.

  7. #7
    Registered User
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    Quote Originally Posted by kris.c
    ok , I understand ur problem, this is what u might have intended to do :

    prog -a -a

    this gives u the reqd o/p..
    I am working with all possibilities that the user may write:
    prog -a-a -- which displays what I wrote in my first post
    How to cover this situation?

  8. #8
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    No help!

  9. #9
    Gawking at stupidity
    Join Date
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    Oregon, USA
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    getopt() is designed to be used a particular way. If you want to parse command line options in some other fashion then you should create your own parser.

    IMHO, telling the user that -a-a isn't valid is handling it.
    If you understand what you're doing, you're not learning anything.

  10. #10
    Registered User
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    130
    Thanks. I got what you mean

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