Assigning pointers from pointers in struct.

This is a discussion on Assigning pointers from pointers in struct. within the C Programming forums, part of the General Programming Boards category; How can I assign a location to a pointer from a pointer within a struct. if n->left points to "node ...

  1. #1
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    Assigning pointers from pointers in struct.

    How can I assign a location to a pointer from a pointer within a struct.

    if n->left points to "node a;"
    how can I make node pointer ptr point to node a?

    if you get my drift.

    also if i have made a node.
    Code:
    node nn;
    nn.val = 5;
    how can i make an existing pointer within a node
    which i have a pointer to point to the new node
    Code:
    int blah (node *mega)
    {
      node nn;
      nn.val = 5;
      mega->left = nn;
      return 0;
    }
    doesnt seem to work. Or is this because the function is destroying the new node nn when it finishes?
    Last edited by Brian; 10-18-2003 at 04:28 AM.

  2. #2
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    Well you wouldn't want to do

    node nn;
    nn.val = 5;
    mega->left = nn;

    Because you're pointing at a local

    But if you did, the syntax would be
    mega->left = &nn;


    This is more usual
    node *nn = malloc( sizeof(*nn) );
    nn->val = 5;
    mega->left = nn;
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  3. #3
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    Brilliant, thanks .

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