由前序遍历和中序遍历构建二叉树（C++语言）

/**
 *作者：魏宝航
 *2020年11月27日,下午15:50
 */
#include<iostream>
using namespace std;
class Node {
public:
    char ch;
    Node* left;
    Node* right;
    Node() {
        ch = '\0';
        left = NULL;
        right = NULL;
    }
    Node(char ch, Node* left, Node* right) {
        this->ch = ch;
        this->left = left;
        this->right = right;
    }
};
//二叉树的前序遍历
void preOrder(Node* root) {
    if (root == NULL) {
        return;
    }
    cout << root->ch << " ";
    preOrder(root->left);
    preOrder(root->right);
}
//二叉树的中序遍历
void midOrder(Node* root) {
    if (root == NULL) {
        return;
    }
    midOrder(root->left);
    cout << root->ch << " ";
    midOrder(root->right);
}
//二叉树的后序遍历
void postOrder(Node* root) {
    if (root == NULL) {
        return;
    }
    postOrder(root->left);
    postOrder(root->right);
    cout << root->ch << " ";
}
//由前序遍历和中序遍历构建二叉树
Node* buildTree(char* pre, char* in, int n) {
    if (n == 0) {
        return NULL;
    }
    Node* root = new Node();
    root->ch = *pre;
    char* p;
    //在中序中找到根节点
    for (p = in; p < in + n; p++) {
        if (*p == *pre) {
            break;
        }
    }
    int left = p - in;//左子树个数
    int right = n - left - 1;//右子树个数
    //递归构建左子树
    root->left = buildTree1(pre + 1, in, left);
    //递归构建右子树
    root->right = buildTree1(pre + left + 1, p + 1, right);
    return root;
}
int main() {
    char a[] = { 'A','B','D','E','C','F' };
    char b[] = { 'D','B','E','A','C','F' };
    Node* root = new Node();
    root = buildTree(a, b, 6);
    preOrder(root);
    midOrder(root);
}