[英]Add nodes to binary search tree c++
I am building a binary search tree. 我正在建立一个二进制搜索树。 Now I am having a problem with adding a node to the tree.
现在我在向树添加节点时遇到问题。
void BinaryTree::add(int value, Node* node) {
if(!node)
node = new Node(value);
else if(node->key < value)
this->add(value, node->rightNode);
else if(node->key > value)
this->add(value, node->leftNode);
}
This code does not seem to work when I call: 当我打电话时,此代码似乎不起作用:
BinaryTree test;
test.add(4, test.root);
test.add(1, test.root);
test.add(5, test.root);
test.add(2, test.root);
test.add(3, test.root);
test.add(7, test.root);
test.add(6, test.root);
After the first add call, the root of the tree 'test' is still empty. 在第一次添加调用之后,树“ test”的根仍然为空。 How shall I change the code so that it will be updated when I call add and the node goes to the correct place of the tree?
我应该如何更改代码,以便在调用add并将节点移至树的正确位置时对其进行更新? Thank you very much!
非常感谢你!
You are passing the Node *
by value here: 您正在按值传递
Node *
:
void BinaryTree::add(int value, Node* node) {
One solution is to pass by reference instead: 一种解决方案是改为通过引用传递:
void BinaryTree::add(int value, Node *& node) {
^
If you pass by value the function is just receiving a copy of the Node *
and so any modification to it will not be reflected back in the calling code. 如果按值传递,则该函数仅接收
Node *
的副本,因此对它的任何修改都不会反映在调用代码中。
Also you might want to think about what happens when value
is equal to the key
. 另外,您可能需要考虑当
value
等于key
时会发生什么。
您递归地调用add函数,但是在那儿我看不到您实际上将leftNode或rightNode分配给传入的节点。
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