二叉树的基本运算及其实现 编程实现：建立二叉树并输出下列二叉树的（1）结点个数；（2）叶子结点个数；（3）深度；（4）先序序列、中序序列和后序序列。用C语言实现

以下是用 C 语言实现建立二叉树并输出相关信息的代码：

#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
    char data;
    struct Node* left;
    struct Node* right;
} Node;

Node* createNode(char data) {
    Node* node = (Node*)malloc(sizeof(Node));
    node->data = data;
    node->left = NULL;
    node->right = NULL;
    return node;
}

Node* createTree() {
    Node* root = createNode('A');
    root->left = createNode('B');
    root->left->left = createNode('D');
    root->left->right = createNode('E');
    root->left->right->left = createNode('G');
    root->right = createNode('C');
    root->right->right = createNode('F');
    return root;
}

int countNodes(Node* root) {
    if (root == NULL) {
        return 0;
    }
    return countNodes(root->left) + countNodes(root->right) + 1;
}

int countLeaves(Node* root) {
    if (root == NULL) {
        return 0;
    }
    if (root->left == NULL && root->right == NULL) {
        return 1;
    }
    return countLeaves(root->left) + countLeaves(root->right);
}

int depth(Node* root) {
    if (root == NULL) {
        return 0;
    }
    int leftDepth = depth(root->left);
    int rightDepth = depth(root->right);
    return (leftDepth > rightDepth) ? (leftDepth + 1) : (rightDepth + 1);
}

void preOrder(Node* root) {
    if (root != NULL) {
        printf("%c ", root->data);
        preOrder(root->left);
        preOrder(root->right);
    }
}

void inOrder(Node* root) {
    if (root != NULL) {
        inOrder(root->left);
        printf("%c ", root->data);
        inOrder(root->right);
    }
}

void postOrder(Node* root) {
    if (root != NULL) {
        postOrder(root->left);
        postOrder(root->right);
        printf("%c ", root->data);
    }
}

int main() {
    Node* root = createTree();
    printf("Number of nodes: %d\n", countNodes(root));
    printf("Number of leaves: %d\n", countLeaves(root));
    printf("Depth: %d\n", depth(root));
    printf("Pre-order traversal: ");
    preOrder(root);
    printf("\n");
    printf("In-order traversal: ");
    inOrder(root);
    printf("\n");
    printf("Post-order traversal: ");
    postOrder(root);
    printf("\n");
    return 0;
}

输出结果为：

Number of nodes: 7
Number of leaves: 3
Depth: 4
Pre-order traversal: A B D E G C F
In-order traversal: D B G E A C F
Post-order traversal: D G E B F C A