我想要一个动态查找表的C语言程序

以下是一个简单的动态查找表的 C 语言程序示例：

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

#define MAX_LEN 100

typedef struct Node {
    char key[MAX_LEN];
    char value[MAX_LEN];
    struct Node *next;
} Node;

Node *create_node(char *key, char *value) {
    Node *new_node = (Node *) malloc(sizeof(Node));
    strcpy(new_node->key, key);
    strcpy(new_node->value, value);
    new_node->next = NULL;
    return new_node;
}

void insert(Node **head, char *key, char *value) {
    Node *new_node = create_node(key, value);
    if (*head == NULL) {
        *head = new_node;
    } else {
        Node *cur = *head;
        while (cur->next != NULL) {
            cur = cur->next;
        }
        cur->next = new_node;
    }
}

void delete(Node **head, char *key) {
    if (*head == NULL) {
        return;
    }
    Node *cur = *head;
    Node *prev = NULL;
    while (cur != NULL && strcmp(cur->key, key) != 0) {
        prev = cur;
        cur = cur->next;
    }
    if (cur == NULL) {
        return;
    }
    if (prev == NULL) {
        *head = cur->next;
    } else {
        prev->next = cur->next;
    }
    free(cur);
}

char *search(Node *head, char *key) {
    while (head != NULL) {
        if (strcmp(head->key, key) == 0) {
            return head->value;
        }
        head = head->next;
    }
    return NULL;
}

void print_list(Node *head) {
    while (head != NULL) {
        printf("%s: %s\n", head->key, head->value);
        head = head->next;
    }
}

int main() {
    Node *head = NULL;
    insert(&head, "apple", "a kind of fruit");
    insert(&head, "banana", "a kind of fruit");
    insert(&head, "carrot", "a kind of vegetable");
    printf("Before deletion:\n");
    print_list(head);
    delete(&head, "banana");
    printf("After deletion:\n");
    print_list(head);
    printf("Search result:\n");
    printf("%s\n", search(head, "carrot"));
    printf("%s\n", search(head, "banana"));
    return 0;
}

该程序使用链表实现动态查找表，可以插入、删除和查找键值对。注意到 `Node` 结构体中的 `key` 和 `value` 数组是固定长度的，如果需要处理不定长字符串，可以使用动态内存分配。