Thread: Dereferencing double pointers

  1. #1
    Registered User
    Join Date
    Sep 2016

    Dereferencing double pointers


    I have a variable that points to a character, i.e.
    char* ptr = &characterInArray;
    Now I want to send the adress of the ptr-variable into a function so I can modify where it points, but my problem is that I don't know how I am supposed to check the adress before what ptr points to. I have tried this for example:
    if (**(ptr - 1) == token)
        //Do something;
    How should I proceed?

    EDIT: To clearify, if ptr points to a character in an array I want to check the previous value in the array by using the pointer.
    Last edited by Kirderf; 12-29-2016 at 09:01 AM.

  2. #2
    Registered User
    Join Date
    Sep 2016
    Funny enough I solved it within a minute after posting this thread. The way I am supposed to look at it is like declaring a variable. To check the preceding value I have to do this:
    if (*(*ptr - 1) == token)
        //Do something

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