AVL tree in C language

Question

Hey all; i am currently doing a project that requires the use of AVL trees , the insert function i wrote for the avl does not seem to be working , it works for 3 or 4 nodes at maximum ;

i would really appreciate your help The attempt is below

Tree insert(Tree t,char name[80],int num)
{
  if(t==NULL)
  {
    t = (Tree)malloc(sizeof(struct node));

    if(t! = NULL)
    {
      strcpy(t->name,name);
      t->num = num;
      t->left = NULL;
      t->right = NULL;
      t->height = 0;
    }
  }
  else if(strcmp(name,t->name)<0)
  {
    t->left = insert(t->left,name,num);

    if((height(t->left)-height(t->right))==2)
      if(strcmp(name,t->left->name)<0)
        t = s_rotate_left(t);
      else
        t = d_rotate_left(t);
  }
  else if(strcmp(name,t->name)>0)
  {
    t->right = insert(t->right,name,num);

    if((height(t->right)-height(t->left))==2)
      if(strcmp(name,t->right->name)>0)
        t = s_rotate_right(t);
      else
        t = d_rotate_right(t);
  }

  t->height = max(height(t->left),height(t->right))+1;

  return t;
}

Answer 1

I don't know what sort of error you're getting, but there are a couple of things that need to be fixed.

You need to deside what you're going to do when the malloc fails. Right now you are setting height on a null pointer in that case.

If height(NULL) returns 0, then you are setting the height on a new node to 0 and then to 1. If it returns -1, then one of those assignments is redundant.

And you're calling strcmp twice for no good reason.

I suspect the real problem is buried in s_rotate_left, d_rotate_left, s_rotate_right, or d_rotate_right.