c语言代码根据我的代码

好的，以下是一个基于你之前提供的C++代码实现爬取当当网图书信息的C语言代码示例。请注意，由于C语言的特殊性，代码结构和使用方式与C++会有所不同。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
#include <libxml/parser.h>
#include <libxml/tree.h>

#define URL "http://book.dangdang.com/"
#define USER_AGENT "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3"
#define BOOK_COUNT 20

struct Book {
    char name[100];
    char author[100];
    char price[20];
};

struct MemoryStruct {
    char *memory;
    size_t size;
};

static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) {
    size_t realsize = size * nmemb;
    struct MemoryStruct *mem = (struct MemoryStruct *) userp;

    mem->memory = realloc(mem->memory, mem->size + realsize + 1);
    if (mem->memory == NULL) {
        printf("Out of memory\n");
        return 0;
    }

    memcpy(&(mem->memory[mem->size]), contents, realsize);
    mem->size += realsize;
    mem->memory[mem->size] = 0;

    return realsize;
}

void parse_xml(char *xml_str, struct Book *book_list) {
    xmlDocPtr doc = xmlReadMemory(xml_str, strlen(xml_str), NULL, NULL, 0);
    xmlNodePtr root_node = xmlDocGetRootElement(doc);

    xmlNodePtr sale_node = root_node->children;
    xmlNodePtr new_node = sale_node->next;
    xmlNodePtr hot_node = new_node->next;

    int i = 0;
    for (xmlNodePtr book_node = sale_node->children; book_node != NULL; book_node = book_node->next) {
        if (i >= BOOK_COUNT) {
            break;
        }
        xmlNodePtr name_node = book_node->children;
        xmlNodePtr author_node = name_node->next;
        xmlNodePtr price_node = author_node->next;
        strcpy(book_list[i].name, xmlNodeGetContent(name_node));
        strcpy(book_list[i].author, xmlNodeGetContent(author_node));
        strcpy(book_list[i].price, xmlNodeGetContent(price_node));
        i++;
    }

    for (xmlNodePtr book_node = new_node->children; book_node != NULL; book_node = book_node->next) {
        if (i >= BOOK_COUNT) {
            break;
        }
        xmlNodePtr name_node = book_node->children;
        xmlNodePtr author_node = name_node->next;
        xmlNodePtr price_node = author_node->next;
        strcpy(book_list[i].name, xmlNodeGetContent(name_node));
        strcpy(book_list[i].author, xmlNodeGetContent(author_node));
        strcpy(book_list[i].price, xmlNodeGetContent(price_node));
        i++;
    }

    for (xmlNodePtr book_node = hot_node->children; book_node != NULL; book_node = book_node->next) {
        if (i >= BOOK_COUNT) {
            break;
        }
        xmlNodePtr name_node = book_node->children;
        xmlNodePtr author_node = name_node->next;
        xmlNodePtr price_node = author_node->next;
        strcpy(book_list[i].name, xmlNodeGetContent(name_node));
        strcpy(book_list[i].author, xmlNodeGetContent(author_node));
        strcpy(book_list[i].price, xmlNodeGetContent(price_node));
        i++;
    }

    xmlFreeDoc(doc);
    xmlCleanupParser();
}

int main() {
    CURL *curl_handle;
    CURLcode res;
    struct MemoryStruct chunk;
    chunk.memory = malloc(1);
    chunk.size = 0;

    curl_global_init(CURL_GLOBAL_ALL);
    curl_handle = curl_easy_init();
    curl_easy_setopt(curl_handle, CURLOPT_URL, URL);
    curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, USER_AGENT);
    curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
    curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *) &chunk);
    res = curl_easy_perform(curl_handle);

    if (res != CURLE_OK) {
        printf("curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
    } else {
        struct Book book_list[60];
        parse_xml(chunk.memory, book_list);
        FILE *fp = fopen("book_info.csv", "w");
        fprintf(fp, "书名,作者,价格\n");
        for (int i = 0; i < BOOK_COUNT * 3; i++) {
            fprintf(fp, "%s,%s,%s\n", book_list[i].name, book_list[i].author, book_list[i].price);
        }
        fclose(fp);
        printf("数据已保存至book_info.csv文件中\n");
    }

    curl_easy_cleanup(curl_handle);
    curl_global_cleanup();
    free(chunk.memory);

    return 0;
}

以上代码使用了C语言的libcurl库和libxml库来实现HTTP请求和XML解析。它首先发送HTTP请求，获取当当网的HTML页面，然后从HTML页面中解析出XML数据，再将XML数据解析为结构体数组，最后将结构体数组保存为.csv文件。请注意，代码中使用了动态内存分配，需要在程序结束时手动释放内存。