This program prints tree in zig zag fashion

zigzagRec.c

void printTreeLevel_iter1(Node *root){
    int h = height(root);
    int i;
    int ltr = 1;
    for(i =1; i<=h; i++){
      printf("\n Level %d :", i);
      /* initially passing it to left to right */
      zigzagRec(root, i, ltr);
      /* For next iteration (level), it will be reversed */
      ltr = !ltr;
      printf("\n");
    }
}

void zigzagRec(Node * node, int desired, int ltr){
  if(node == NULL) return;

   if (desired ==1)
      printf("%d  ", node->value);
      /* Based on the flag call the recursive function accordingly */
      if(ltr){
        zigzagRec(node->left, desired -1, ltr);
        zigzagRec(node->right, desired -1, ltr);
       }
       else{
          zigzagRec(node->right, desired -1, ltr);
          zigzagRec(node->left, desired -1, ltr);
       }
}