C語言作為一種底層編程語言，可以操作底層資源，包含網絡資源。下面我們來介紹如何利用C語言訪問網站獲取JSON。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
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");
exit(EXIT_FAILURE);
}
memcpy(&(mem->memory[mem->size]), contents, realsize);
mem->size += realsize;
mem->memory[mem->size] = '\0';
return realsize;
}
int main(void) {
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, "https://api.github.com/");
curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);
curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");
res = curl_easy_perform(curl_handle);
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
} else {
printf("%lu bytes retrieved\n", (unsigned long) chunk.size);
printf("%s\n", chunk.memory);
}
curl_easy_cleanup(curl_handle);
free(chunk.memory);
curl_global_cleanup();
return 0;
}

以上為使用CURL庫實現訪問網站獲取JSON的代碼，主要是通過函數writeback將獲取到的JSON存到chunk.memory中，使用printf打印獲取到的JSON內容。