Thread: That does this double pointer means ?

  1. #1
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    That does this double pointer means ?

    i understand pointer is location of a memory. here in following,
    *ia and *ib is location in memory but after that what is
    (*const char and double **)a;
    and
    *(const char **)b;
    means ?


    Code:
     
    const char *ia = *(const char **)a;
    const char *ib = *(const char **)b;
    Thanks

  2. #2
    C++ Witch laserlight's Avatar
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    I think it means that you need to work through an introductory book on C, so that you are introduced to type casts and can reason out pointers to pointers.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    I asked you. so i expect answer from you!

  4. #4
    C++ Witch laserlight's Avatar
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    I have not offered to answer your questions to your precise satisfaction, and you have given me no consideration in that you are not paying for me to provide you with programming tuition, so you can expect all you like, but there is no contract by which I have promised to answer your questions the way you would like them answered. If I so choose, I will answer them in the way that I think would best help you.

    My point here is that you appear to lack some rudimentary knowledge of C, of the type that can be obtained by working through introductory material such as books. As rstanley recommended in another topic, you might even need some guidance from an instructor, perhaps by paying for a course if one is available. It is only after you have obtained such understanding -- or at least are obviously in the process of doing so -- that it makes sense for you to come back here with a more advanced question, or at least a question that shows that you are learning the basic material.

    What you are doing now is just dumping question after question without regard for anyone else. That makes you a help vampire. Don't be a help vampire. Help yourself first by getting your own basic knowledge up to speed so that you can learn how to ask smart questions.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  5. #5
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    I appreciate your advice thought. Thanks !

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