看看这棵二叉树：
给定根节点，怎样将这棵二叉树拷贝出一棵新的二叉树？
不多逼逼，看代码：
先看二叉树节点结构体和实现代码：
typedef struct BinaryTreeNode { char data; //数据 struct BinaryTreeNode *left; //左孩子 struct BinaryTreeNode *right; //右孩子 }Node; //拷贝二叉树 Node * copyBinaryTree(Node *root) { if (NULL == root) { return NULL; } Node *leftNode = copyBinaryTree(root->left); Node *rlghtNode = copyBinaryTree(root->right); Node *newTree = (Node*)malloc(sizeof(Node)); if (NULL == newTree) { printf("空间分配失败\n"); return NULL; } newTree->left = leftNode; //拷贝左子树 newTree->right = rlghtNode; //拷贝右子树 newTree->data = root->data; //拷贝数据 return newTree; //返回新树 }二叉树的节点空间是开辟在堆区的，所以应该手动释放。
看下释放的代码：
//释放二叉树 void freeTree(Node *root) { if (NULL == root) { return; } freeTree(root->left); //释放左子树 freeTree(root->right); //释放右子树 free(root); //释放根节点 root = NULL; }测试下代码是否正确：（完整代码）
#include<iostream> using namespace std; typedef struct BinaryTreeNode { char data; //数据 struct BinaryTreeNode *left; //左孩子 struct BinaryTreeNode *right; //右孩子 }Node; //中序遍历二叉树 void inOrder(Node *root) { if (NULL == root) { return; } inOrder(root->left); printf("%c ",root->data); inOrder(root->right); } //拷贝二叉树 Node * copyBinaryTree(Node *root) { if (NULL == root) { return NULL; } Node *leftNode = copyBinaryTree(root->left); Node *rlghtNode = copyBinaryTree(root->right); Node *newTree = (Node*)malloc(sizeof(Node)); if (NULL == newTree) { printf("空间分配失败\n"); return NULL; } newTree->left = leftNode; //拷贝左子树 newTree->right = rlghtNode; //拷贝右子树 newTree->data = root->data; //拷贝数据 return newTree; //返回新树 } //释放二叉树 void freeTree(Node *root) { if (NULL == root) { return; } freeTree(root->left); //释放左子树 freeTree(root->right); //释放右子树 free(root); //释放根节点 root = NULL; } int main() { //准备数据 Node nodeA = { 'A',NULL,NULL }; Node nodeB = { 'B',NULL,NULL }; Node nodeC = { 'C',NULL,NULL }; Node nodeD = { 'D',NULL,NULL }; Node nodeE = { 'E',NULL,NULL }; Node nodeF = { 'F',NULL,NULL }; Node nodeG = { 'G',NULL,NULL }; Node nodeH = { 'H',NULL,NULL }; Node nodeI = { 'I',NULL,NULL }; //建立关系 nodeA.left = &nodeB; nodeA.right = &nodeC; nodeB.left = &nodeD; nodeB.right = &nodeE; nodeC.left = &nodeF; nodeC.right = &nodeG; nodeF.left = &nodeH; nodeF.right = &nodeI; //调用函数 printf("中序遍历源二叉树结果为：\n"); inOrder(&nodeA); printf("\n"); printf("中序遍历拷贝二叉树："); Node *copyRoot = copyBinaryTree(&nodeA); inOrder(copyRoot); printf("\n"); freeTree(copyRoot); system("pause"); return 0; }测试结果：
