二叉树的递归遍历与复制

#include <iostream>
 
//定义树的数据结构
struct BiTNode
{
    int data;
    struct BiTNode *lchild, *rchild;
};
 
typedef struct BiTNode  BiTNode;
typedef struct BiTNode* BiTree;
 
 
//前序遍历
void preOrder(BiTNode *root)
{
    if (root == NULL)
    {
        return;
    }
    printf("%d ", root->data);
    preOrder(root->lchild);
    preOrder(root->rchild);
}
 
//中序遍历
void inOrder(BiTNode *root)
{
    if (root == NULL)
    {
        return;
    }
    inOrder(root->lchild);
    printf("%d ", root->data);
    inOrder(root->rchild);
}
//后序遍历
void posOrder(BiTNode *root)
{
    if (root == NULL)
    {
        return;
    }
    posOrder(root->lchild);
    posOrder(root->rchild);
    printf("%d ", root->data);
}
//创建拷贝函数
BiTNode* CopyTree(BiTNode *root)
{
    BiTNode *newNode = NULL;
    BiTNode *newLc = NULL;
    BiTNode *newRc = NULL;
 
    if (root == NULL)
    {
        return NULL;
    }
    //拷贝左子树
    if (root->lchild != NULL)
    {
        newLc = CopyTree(root->lchild);
    }
    else
    {
        newLc = NULL;
    }
 
    //拷贝右子树
    if (root->rchild != NULL)
    {
        newRc = CopyTree(root->rchild);
    }
    else
    {
        newRc = NULL;
    }
    
    //创建动态内存
    newNode = (BiTNode * )malloc(sizeof(BiTNode));
    if (newNode == NULL)
    {
        return NULL;
    }
 
    newNode->lchild = newLc;
    newNode->rchild = newRc;
    newNode->data = root->data;
 
    return newNode;
}
 
 
 
void main()
{
    BiTNode t1, t2, t3, t4, t5;
    memset(&t1, 0, sizeof(BiTNode));
    memset(&t2, 0, sizeof(BiTNode));
    memset(&t3, 0, sizeof(BiTNode));
    memset(&t4, 0, sizeof(BiTNode));
    memset(&t5, 0, sizeof(BiTNode));
    t1.data = 1;
    t2.data = 2;
    t3.data = 3;
    t4.data = 4;
    t5.data = 5; 
 
    t1.lchild = &t2;
    t1.rchild = &t3;
    t2.lchild = &t4;
    t2.rchild = &t5;
    printf("Old Tree's preOrder:
");
    preOrder(&t1);
    printf("
");
    printf("Old Tree's inOrder:
");
    inOrder(&t1);
    printf("
");
    printf("Old Tree's posOrder:
");
    posOrder(&t1);
    printf("
");
    printf("Old Tree:
");
    preOrder(&t1);
    printf("
");
    BiTNode* newTree = CopyTree(&t1);
    printf("New Tree:
");
    preOrder(newTree);
 
 
    system("pause");
}