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To start with, I am trying to read a binary tree from file (noob question, I know, but I dont know what I am doing wrong), but it does not work at all, it keeps crashing. The thing is, I got to read the family tree from the file and then put it in preorder, inorder and post order accordingly.For now I am trying to do it with integers, one step at a time. The problems seems to be at my create function, which is:

NodeT *createBinTree(int branch, NodeT *parent) {
    int id;
    FILE *f;
    f=fopen("data.in","r");
    while (!feof(f)) {
            fscanf(f,"%d",&(parent->id));

    fscanf(f,"%d",&id);
    if (id == 0)
        return NULL;
    else {
        p = (NodeT*)malloc(sizeof(NodeT));
        if (p==NULL)
            fatalError("Out of space in createBinTree");
        p->id = id;
        p->left = createBinTree(1, p);
        p->right = createBinTree(2, p);
    }}
    close(f);
   return p;
}

The function that I had was reading it from input stream, like:

NodeT *createBinTree(int branch, NodeT *parent) {
    if (branch == 0)
        printf("Root identifier [0 to end] = ");
    else
        if (branch == 1)
            printf("Left child of %d [0 to end] =", parent->id);
        else
             printf("Right child of %d [0 to end] =", parent->id);
    scanf("%id", &id);
    if (id == 0)
        return NULL;
    else {
        p = (NodeT *)malloc(sizeof(NodeT));
        if (p == NULL)
            fatalError("Out of space in createBinTree");
        p->id = id;
        p->left = createBinTree(1,p);
        p->right = createBinTree(2,p);
    }
    return p;
}

But it seems I don't really know how to transfigure the latest so it can read from file. Any help will be much appreciated. How I am calling the function:

NodeT *root;
root = createBinTree(0, NULL);

For reference, my data.in is: 1 2 4 8 0 0 9 0 0 5 10 0 0 11 0 0 3 6 12 0 0 13 0 0 7 14 0 0 15 0 0. Please be nice, I am a newbie at this. :c

Yukilikespie
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  • `while (!feof(f)) {` always wrong. – chqrlie Dec 01 '15 at 14:58
  • They say you shouldn't case the result of `malloc()` in C. http://stackoverflow.com/questions/605845/do-i-cast-the-result-of-malloc – MikeCAT Dec 01 '15 at 14:58
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    `p` is not defined, I hope it is not a global variable! – chqrlie Dec 01 '15 at 14:58
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    Opening `data.in` every time `createBinTree()` is called and using `close()` instead of `fclose()` to close it are bad ideas. – MikeCAT Dec 01 '15 at 15:00
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    Open the file outside of `createBinTree()`. – chqrlie Dec 01 '15 at 15:00
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    Considering that you call `createBinTree(0, NULL)` it's no surprise that `&(parent->id))` crashes. – Carey Gregory Dec 01 '15 at 15:02
  • @chqrlie 1. That while worked before, but I am also using while(fscanf(f,"%d",id) != -1). 2. It put it as being a local variable. 3. I did that but still does not work. – Yukilikespie Dec 01 '15 at 15:13
  • @MikeCAT I fixed the close part, and I opened it outside the function, but still does not work. – Yukilikespie Dec 01 '15 at 15:14
  • @CareyGregory How should I write it then? I tried the function just with the integer variable, but still does not work. Don't really know what to put there besides NULL. – Yukilikespie Dec 01 '15 at 15:15
  • Well, think the problem through. You can't read data into memory you haven't allocated. Until you fix that nothing else will matter. – Carey Gregory Dec 01 '15 at 15:16
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    You need to pass `&id` to `fscanf`. Furthermore, `while(fscanf(f,"%d",&id) != -1)` will cause an infinite loop if a non digit non space character is present in the input. – chqrlie Dec 01 '15 at 15:26

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