C++ delete all nodes from binary tree

Question

Hey Im writing a binary tree in c++ and have some problems with removing all nodes. I tried to use the following function for that:

void RemoveAll() { RemoveAll(Root); }
void RemoveAll(Node *node)
  {
  if (!node) return;

  RemoveAll(node->Left);
  RemoveAll(node->Right);
  delete node;
  }

And my printing functions:

void PreOrder() { PreOrder(Root); }
void PreOrder(Node *node)
  {
  if (!node) return;

  std::cout << node->Element << std::endl;
  PreOrder(node->Left);
  PreOrder(node->Right);
  }

void InOrder() { InOrder(Root); }
void InOrder(Node *node)
  {
  if (!node) return;

  InOrder(node->Left);
  std::cout << node->Element << std::endl;
  InOrder(node->Right);
  }

void PostOrder() { PostOrder(Root); }
void PostOrder(Node *node)
  {
  if (!node) return;

  PostOrder(node->Left);
  PostOrder(node->Right);
  std::cout << node->Element << std::endl;
  }

The problem is that if I run a printing function afterwards to see if the nodes are really deleted I get an Exception which tells me that the given node was 0xFFFFFFFFFFFFFFF7. Any ideas why? Thanks in advance.

Answer 1

Thanks to Jarod42 and 0x499602D2 who provided the answer.

The final solution looks like this for all future users who have the same problem:

void RemoveAll() { RemoveAll(Root); }
void RemoveAll(Node *&node)
  {
  if (!node) return;
                     
  RemoveAll(node->Left);
  RemoveAll(node->Right);
  
  delete node;
  node = nullptr;
  }