libcurl uninitialized variable curl error - c++

Question

I am trying to make a HTTP Request to retrieve some JSON data; I get the error that curl variable is not initialized though I easy_init() it. Any help on how to go around this error would be very kind!!
Below is my code:
#pragma once
#include "stdafx.h"
#include "RequestJson.h"
#include <string.h>
#include <include/curl/curl.h>
#include <fstream>
#include <iostream>
#include <sstream>
using namespace std;
class RequestJson
{
public:
static std::string RequestJsonString(std::string URL)
{
//set to get the JSON Response on listed loans; open a CSV file and read unemployment and other indices.
::CURL *curl;
CURLcode res;
struct curl_slist *headers = NULL;
std::ostringstream oss;
//curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
curl_slist_append(headers, "Accept: application/json");
curl_slist_append(headers, "Content-Type: application/json");
curl_easy_cleanup(curl);
if (curl)
{
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_URL, URL.c_str());
curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writer); //define a write-function below.
res = curl_easy_perform(curl);
if (CURLE_OK == res)
{
char *ct;
res = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &ct);
if ((CURLE_OK == res) && ct)
{
return *DownloadedResponse;
}
}
}
}
//parse the JSON String and return the downloaded string.
static std::string *DownloadedResponse;
static int writer(char *data, size_t size, size_t nmemb, std::string *buffer_in)
{
if (buffer_in != NULL)
{
buffer_in->append(data, size * nmemb);
DownloadedResponse = buffer_in;
return size * nmemb;
}
return 0;
}
};

Answer 1

From the curl_easy_cleanup reference:
This function must be the last function to call for an easy session. It is the opposite of the curl_easy_init function and must be called with the same handle as input that a curl_easy_init call returned.
[Emphasis mine]
When you call curl_easy_cleanup it cleans up all resources allocated by curl_easy_init. After that you can't use the CURL pointer any more.
As the reference says: Put it last, when you're done.