把二叉树打印成多行

题目描述：从上到下按层打印二叉树，同一层的结点按从左到右的顺序打印，每一层打印到一行，例如：

void Print(){if (_root == NULL)return;queue<Node*>q;q.push(_root);int NextLevel = 0; //下一行结点的个数int CurLevel = 1;  //当前行结点的个数while (!q.empty()){Node* front = q.front();cout << front->_value << " ";q.pop();CurLevel--;if (front->_left){q.push(front->_left);NextLevel++;}if (front->_right){q.push(front->_right);NextLevel++;}if (CurLevel == 0) //说明该行的结点都已被打印{printf("\n");CurLevel = NextLevel;NextLevel = 0;}}}