C ++二叉树递归析构函数问题

Question

I made a binary tree class which holds: int value, BinaryTree* left , BinaryTree* right .

class BinaryTree {
private:
     int value;
     BinaryTree* left;
     BinaryTree* right;
     bool isVisited;
public:
     BinaryTree();
     BinaryTree createComplete(int n);
     ~BinaryTree();
}

My destructor is :

BinaryTree::~BinaryTree() {
delete left;
delete right;   
}

When running in clion it works perfectly, but in my terminal I get a segfault (core dumped). Everywhere I looked people claimed that this should be the destructor. Any elaboration would help!

I am not a stackoverflow expert , I updated my ~BinaryTree function to still gets a segfault :

BinaryTree::~BinaryTree() {
if (right != NULL) {
   delete right;
}
if (left != NULL) {
   delete left;
}

}

Answer 1

First of all your current implementation is not that of a complete tree. It is a node, thus I suggest renaming it to BinaryTreeNode and using it to construct a new class BinaryTree, that keeps track of the root and allows you to recursively deallocate the tree.

Having said that your destructor most likely segfaults because you are blindly attempting to delete a pointer.

First make sure you initialize left and right to nullptr. Then you do if(left != nullptr) { delete left }

Answer 2

Without seeing your constructor, I assume you don't initialize your node's children to NULL. That might mean that the uninitialized nodes left and right at the bottom leaves have a random value in them. When the destructor runs, it will try to free the memory that the random garbage in the nodes point to.

Try initializing your child nodes to NULL when ctoring nodes, then making a check for it like monoceres suggested. It will also be good to set the pointer to NULL after delete to avoid situation of erronous double delete

Answer 3

因此，在调试之后，我注意到每个正确的孩子都失去了它的节点，这在进行预遍历时是可以的，但是在删除它会引起问题时，感谢大家的帮助！