按先序次序建立一棵二叉树，输入时，以井号表示空指针。对其进行后序遍历，并统计叶子结点的个数。C语言实现

以下是基于递归实现的C代码：

#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE 100

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

Node* createTree() {
    char ch;
    Node* root;
    scanf("%c", &ch);
    if (ch == '#') {
        root = NULL;
    } else {
        root = (Node*)malloc(sizeof(Node));
        root->data = ch;
        root->left = createTree();
        root->right = createTree();
    }
    return root;
}

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

int main() {
    Node* root = createTree();
    int leafNum = postOrder(root);
    printf("叶子节点个数为：%d\n", leafNum);
    return 0;
}

输入示例：`AB#C##DE#F##G###`

输出示例：`叶子节点个数为：4`