btree.cpp


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/* btree.cpp
 * Date: 2021-11-22
 * Author: Aryadev Chavali
 */


enum Order
{
  LT,
  GT,
  EQ
};

template <typename T>
struct BinaryTree
{
  T value;
  BinaryTree<T> *left, *right;
  enum Order (*compare)(T, T);
  ~BinaryTree()
  {
    delete left;
    delete right;
  }
};

template <typename T>
BinaryTree<T> *insert(BinaryTree<T> *tree, T value)
{
  BinaryTree<T> **node = &tree;
  switch (tree->compare(value, tree->value))
  {
  case LT:
    node = &tree->left;
    break;
  case EQ:
  case GT:
    node = &tree->right;
    break;
  }

  if (*node) {
    *node = insert(*node, value);
    return tree;
  }
  *node = new BinaryTree<T>;
  (*node)->value = value;
  (*node)->left = (*node)->right = nullptr;
  (*node)->compare = tree->compare;
  return tree;
}