创建二叉树，分别以先序遍历、中序遍历、后序遍历访问二叉树，并输出二叉树的叶子结点及叶子结点的个数的c++源代码

以下是创建二叉树，并分别以先序遍历、中序遍历、后序遍历访问二叉树的c++源代码：

#include<iostream>
using namespace std;

//定义二叉树结构体
struct TreeNode {
    char data;
    TreeNode *left;
    TreeNode *right;
};

//创建二叉树
TreeNode *createTree() {
    char ch;
    TreeNode *root = NULL;
    cin >> ch;
    if (ch != '#') {
        root = new TreeNode();
        root->data = ch;
        root->left = createTree();
        root->right = createTree();
    }
    return root;
}

//先序遍历二叉树
void preorder(TreeNode *root) {
    if (root == NULL) {
        return;
    }
    cout << root->data << " ";
    preorder(root->left);
    preorder(root->right);
}

//中序遍历二叉树
void inorder(TreeNode *root) {
    if (root == NULL) {
        return;
    }
    inorder(root->left);
    cout << root->data << " ";
    inorder(root->right);
}

//后序遍历二叉树
void postorder(TreeNode *root) {
    if (root == NULL) {
        return;
    }
    postorder(root->left);
    postorder(root->right);
    cout << root->data << " ";
}

//统计叶子结点个数并输出叶子结点
int countLeaves(TreeNode *root) {
    if (root == NULL) {
        return 0;
    }
    if (root->left == NULL && root->right == NULL) {
        cout << root->data << " ";
        return 1;
    }
    return countLeaves(root->left) + countLeaves(root->right);
}

int main() {
    TreeNode *root = createTree();
    cout << "先序遍历：";
    preorder(root);
    cout << endl;
    cout << "中序遍历：";
    inorder(root);
    cout << endl;
    cout << "后序遍历：";
    postorder(root);
    cout << endl;
    cout << "叶子结点：";
    int leaves = countLeaves(root);
    cout << endl;
    cout << "叶子结点个数：" << leaves << endl;
    return 0;
}

在程序中，#表示空节点。当输入#时，说明该节点为空，返回NULL。在主函数中，先创建二叉树，再分别以先序遍历、中序遍历、后序遍历访问二叉树，并输出叶子结点及叶子结点的个数。