二叉树的层次遍历

参考视频：https://www.youtube.com/watch?v=86g8jAQug04

struct Node{  char data;  Node* left;  Node* right;}void levelOrder(Node* root){  if(root==null) return ;  queue<Node *> Q;  Q.push(root);  while(!Q.empty()){     Node* current=Q.front();     if(current->left!=null)         Q.push(current->left);     if(current->right!=null)       Q.push(current->right);     Q.pop();  }}