二叉树的三种遍历方式

#include <iostream>
using namespace std;

struct tree
{
    int data;
    struct tree *left;
    struct tree *right;
};
typedef struct tree Tree;

//创建二叉树
Tree *CreateTree(int a[], int len)
{
    Tree *node[100] = {0};
    for (int i = 0; i < len; i++)
    {
        node[i] = (Tree *)malloc(sizeof(Tree));
        if (NULL == node[i])
        {
            return;
        }
        node[i]->data = a[i];
        node[i]->left = NULL;
        node[i]->right = NULL;
    }
    for (int i = 0; i < len/2; i++)
    {
        node[i]->left = node[2*i + 1];
        node[i]->right = node[2*i + 2];
    }
    return node[0];
}

//先序遍历
void PreOrder(Tree *root)
{
    if (root == NULL)
        return;
    printf("%d ", root->data);
    PreOrder(root->left);
    PreOrder(root->right);
}

//中序遍历
void MidOrder(Tree *root)
{
    if (root == NULL)
        return;
    MidOrder(root->left);
    printf("%d ", root->data);
    MidOrder(root->right);
}

//后续遍历
void BackOrder(Tree *root)
{
    if (root == NULL)
        return;
    BackOrder(root->left);
    BackOrder(root->right);
    printf("%d ", root->data);
}

int main()
{
    int data[10] = {0};
    Tree *root;
    printf("请输入信息：\n");
    for (int i = 0; i < 10; i++)
    {
        scanf("%d", &data[i]);
    }
    root = CreateTree(data, sizeof(data) / sizeof(data[0]));

    printf("先序：\n");
    PreOrder(root);
    printf("\n");

    printf("中序：\n");
    MidOrder(root);
    printf("\n");

    printf("后序：\n");
    BackOrder(root);
    printf("\n");
}