Accessing elements in an array of pointers to arrays

This is a discussion on Accessing elements in an array of pointers to arrays within the C Programming forums, part of the General Programming Boards category; I have an array of pointers that point to arrays of characters and what I'd like to do is access ...

  1. #1
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    Accessing elements in an array of pointers to arrays

    I have an array of pointers that point to arrays of characters and what I'd like to do is access the 4th letter in the 3rd word and change it. I've tried tons of combinations but I can't seem to get a pointer to what I want, any suggestions. Thanks. PS I know the code doesn't print anything out yet.

    Code:
    int main()
    {
       char *words[] = {"One", "Two", "Three", "Four"};
       (*words[2]) + 3 = 'D'; //I'd like to turn the 1st 'e' in Three into a D
       return 0;
    }

  2. #2
    Registered User C_ntua's Avatar
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    It would be
    Code:
    *(words[2]+3) = 'D';
    or simpler and better
    Code:
    words[2][3] = 'D';
    think that words is a char**, words[] is a char* and words[][] is a char

  3. #3
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    Those are both incorrect (for me anyways) and all give segmentation fault errors. I even tried changing char *words[] to char **words[] and I just get different errors using that.

  4. #4
    a_capitalist_story
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    Initialized char *s are constant and cannot be modified. The string is loaded into read-only memory.

  5. #5
    ATH0 quzah's Avatar
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    You have an array of pointers to characters, not a 2D array of characters. You assign those pointers string literals, which you shouldn't attempt to modify. You can make the pointer point elsewhere, but you cannot change what your string literals contain.


    Quzah.
    Hope is the first step on the road to disappointment.

  6. #6
    Registered User
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    Maybe what you want is more like:

    Code:
    int main()
    {
      int i;
      char words[4][6] = {{"One"}, {"Two"}, {"Three"}, {"Four"}};
      (words[2][3] = 'D'; //I'd like to turn the 1st 'e' in Three into a D
    
      for(i=0;i<4;i++)
        printf("\n %s", words[i]);
    
       return 0;
    }

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