二叉树的遍历(算法导论第三版12.1-4)

1⃣️先序遍历

template<typename T>
void preorder_tree_wald(BinaryTreeNode<T> *node)
{if(node!= nullptr){std::cout<<node->key<<" ";preorder_tree_wald(node->left);preorder_tree_wald(node->right);}
}

2⃣️后序遍历

template<typename T>
void postorder_tree_walk(BinaryTreeNode<T> *node)
{if(node!= nullptr){postorder_tree_walk(node->left);postorder_tree_walk(node->right);std::cout<<node->key<<" ";}
}

3⃣️中序遍历

template<typename T>
void inorder_tree_walk(BinaryTreeNode<T> * node)
{if(node!= nullptr){inorder_tree_walk(node->left);std::cout<<node->key<<" ";inorder_tree_walk(node->right);}
}

测试代码

    BinaryTreeNode<int>* node1 = new BinaryTreeNode<int>(1);BinaryTreeNode<int>* node2 = new BinaryTreeNode<int>(2);BinaryTreeNode<int>* node3 = new BinaryTreeNode<int>(3);BinaryTreeNode<int>* node4 = new BinaryTreeNode<int>(4);BinaryTreeNode<int>* node5 = new BinaryTreeNode<int>(5);BinaryTreeNode<int>* node6 = new BinaryTreeNode<int>(6);BinaryTreeNode<int>* node7 = new BinaryTreeNode<int>(7);BinaryTreeNode<int>* node8 = new BinaryTreeNode<int>(8);node1->left = node2;node1->right = node3;node2->parent = node1;node2->left = node4;node2->right = node5;node3->parent = node1;node3->left = node6;node3->right = node7;node4->parent = node2;node4->left = node8;node5->parent = node2;node6->parent = node3;node7->parent = node3;node8->parent = node4;inorder_tree_walk(node1);cout<<endl;preorder_tree_wald(node1);cout<<endl;postorder_tree_walk(node1);cout<<endl;

辅助类
BinaryTreeNode链接地址
最大的区别在于输出的子树根的位置不同