如何在c++中使用libcurl发送和接收POST请求？

#include <curl/curl.h>
#include <iostream>

size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* response) {
    size_t totalSize = size * nmemb;
    response->append((char*)contents, totalSize);
    return totalSize;
}

int main() {
    CURL* curl = curl_easy_init();
    if (curl) {
        std::string url = "http://example.com/api";
        std::string postData = "key1=value1&key2=value2";

        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
        curl_easy_setopt(curl, CURLOPT_POST, 1);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postData.c_str());

        std::string response;
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);

        CURLcode res = curl_easy_perform(curl);
        if (res == CURLE_OK) {
            long responseCode;
            curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &responseCode);
            std::cout << "Response Code: " << responseCode << std::endl;
            std::cout << "Response Body: " << response << std::endl;
        } else {
            std::cerr << "Request failed: " << curl_easy_strerror(res) << std::endl;
        }

        curl_easy_cleanup(curl);
    }

    return 0;
}