使用c语言编写代码实现二叉树的以下功能：二叉树的创建、二叉树的三种递归遍历、二叉树的复制、统计二叉树的结点数，统计二叉树叶子节点数、计算二叉树的深度、交换二叉树每个结点的左孩和右孩。

以下是使用C语言实现二叉树的各种功能的代码：

1. 二叉树的创建

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

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};

struct TreeNode* createTree() {
    int val;
    scanf("%d", &val);
    if (val == -1) {
        return NULL;
    }
    struct TreeNode *node = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    node->val = val;
    node->left = createTree();
    node->right = createTree();
    return node;
}

2. 二叉树的三种递归遍历

void preorderTraversal(struct TreeNode* root) {
    if (root == NULL) {
        return;
    }
    printf("%d ", root->val);
    preorderTraversal(root->left);
    preorderTraversal(root->right);
}

void inorderTraversal(struct TreeNode* root) {
    if (root == NULL) {
        return;
    }
    inorderTraversal(root->left);
    printf("%d ", root->val);
    inorderTraversal(root->right);
}

void postorderTraversal(struct TreeNode* root) {
    if (root == NULL) {
        return;
    }
    postorderTraversal(root->left);
    postorderTraversal(root->right);
    printf("%d ", root->val);
}

3. 二叉树的复制

struct TreeNode* cloneTree(struct TreeNode* root) {
    if (root == NULL) {
        return NULL;
    }
    struct TreeNode *node = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    node->val = root->val;
    node->left = cloneTree(root->left);
    node->right = cloneTree(root->right);
    return node;
}

4. 统计二叉树的结点数

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

5. 统计二叉树叶子节点数

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

6. 计算二叉树的深度

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

7. 交换二叉树每个结点的左孩和右孩

void swapChildren(struct TreeNode* root) {
    if (root == NULL) {
        return;
    }
    struct TreeNode *temp = root->left;
    root->left = root->right;
    root->right = temp;
    swapChildren(root->left);
    swapChildren(root->right);
}