problems reading names from a file to insert into a binary tree

Question

Reading from a file of names, I'm trying to put those name into a binary search tree. But for some reason when I read the file, I am starting with a random junk file node:

TreeNode* read_from_file(const char* file){
    File *fp = fopen(file,"r");
    char buffer[MAX_NAME_LEN];
    TreeNode *t = NULL;

    t = insert(t,buffer); //insert is just your standard function for creating a binary tree

    while(!feof(fp)){
          fscanf(fp,"%s",buffer);
          insert(t,buffer);
          }

    return t;
    fclose(fp);
}

When I then print out the tree I am getting a seemingly random node in my list such as '{ or ÐFÀ> along with the name nodes when the inputed file only has names like bob matt and nick.

Answer 1

You insert buffer before you fill it with anything. The random trash is just what happens to be in that array before you do anything with it yourself.

Obvious solution: remove the first insert. (As a matter of fact, I can't think of a reason why it's there anyway.) Since you need to save the starting node t somewhere, to return it at the end, you need to re-think your loop. Either insert a dummy string as 'root' (but not using the uninitialized buffer!), or do an fscanf before the loop.