send http request in C

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

size_t write_callback(char ptr, size_t size, size_t nmemb, void userdata) {
    FILE file = (FILE)userdata;
    return fwrite(ptr, size, nmemb, file);
}

int main() {
    CURL *curl;
    FILE *file;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        curl_easy_setopt(curl, CURLOPT_URL, "http://www.example.com");
        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);

        file = fopen("response.txt", "wb");
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, file);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);

        res = curl_easy_perform(curl);

        curl_easy_cleanup(curl);
        fclose(file);
    }

    return 0;
}