problem returning struct member from function

This is a discussion on problem returning struct member from function within the C Programming forums, part of the General Programming Boards category; I have a binary search tree made up of struct tree_st nodes. The struct has members TData (which is just ...

  1. #1
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    problem returning struct member from function

    I have a binary search tree made up of struct tree_st nodes. The struct has members TData (which is just a typedefed int) and pointers to left and right trees. Everything is working fine; test program takes int values and puts them in the tree and then prints out an in-order traversal.

    But now I'm trying to add findMin and findMax functions. These also work just fine, as long as I print out the min or max in the function. If I try to return the value and print it out in main, I get the address instead! Weird.

    Here's the findMin function:


    Code:
    Tdata 
    findMin(const Tree t) 
    {
      if (t == NULL) return -1;
      if (t->left == NULL)
      {
    	printf("min: %d\n",t->data);       		
    	return t->data;
      }
       else findMin(t->left);
    }

    In main, I do this:
    Code:
    printf("The min value is %d\n", findMin(t));
    (The findMax function does the same but goes to the right.)

    I put the printf in findMin as a test, and sure enough, it prints out the actual integer minimum. But then, returning t->data to main and printing it out prints out an address!!

    Any guidance on this would be much appreciated. Thanks.

  2. #2
    *******argv[] - hu? darksaidin's Avatar
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    Just a guess: Is t->data of type TData or int ?

    Have you tried int findMin(const Tree t) ? It may be that printf doesn't recognize your data type as an integer. I know that at least cout (c++) would not and print gibberish.

  3. #3
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    >>>>It may be that printf doesn't recognize your data type as an integer.

    If its typedef'ed, I dont think it should be a problem. But thats only a guess. Could you post the entire/relevant code here please?

    Anoop.

  4. #4
    Code Goddess Prelude's Avatar
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    Can we see the struct and typedef declarations?
    My best code is written with the delete key.

  5. #5
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    declarations

    Here are the type declarations:

    Code:
    typedef int Tdata;
    
    typedef struct tree_st
    {
    	Tdata data;
    	struct tree_st * left;
    	struct tree_st * right;
    } * Tree;
    The problem is not the printf; the numbers print out fine in the printf. It's once the number is returned that I get the address... at least, I think it's the address of the value. It's a large integer... don't think random garbage would look like that.

    Haven't tried returning an int because what's the point of a typedef if you can't pass it around!? But, I guess I'll give it a shot.

    thanks

  6. #6
    Comment your source code! Lynux-Penguin's Avatar
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    just a shot in the dark...
    Code:
    typedef int Tdata;
    
    typedef struct
    {
    	Tdata data;
    	struct tree_st * left;
    	struct tree_st * right;
    } Tree;
    Last edited by Lynux-Penguin; 08-24-2003 at 12:06 PM.
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  7. #7
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    Ack! Have to "return" the recursive call! Duh. If it wuz a snake it woulda bit me. Thanks.

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