for loop Download file from string link - c++

Question

I need to batch download a file from a link and this link is in a string, how do I do it? I downloaded curl but I don't know how to use it.
string goes this way:
www.example.com/item1.jpeg
www.example.com/item2.jpeg
and so on.
I don't need to change the output names, they can stay as they are.
I'm using this:
CURL curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, c_str(link));
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
}
But I'm getting the error:
[Error] 'c_str' was not declared in this scope
My whole script is:
#include <iostream>
#include <string>
#include <stdio.h>
#include <stdlib.h>
#include <curl/curl.h>
using namespace std;
int main ()
{
char buffer[21];
int start;
int end;
int counter;
string site;
site = "http://www.example.com/";
string extension;
extension= ".jpeg";
string link;
cout << "Start: ";
cin >> start;
cout << "End: ";
cin >> end;
for (counter=start; counter<=end; counter++)
{
std::string link = site+itoa(counter, buffer, 10)+extension;
cout << link;
cout << "\n";
//////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////
CURL curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, link.c_str());
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
}
//////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////
}
return 0;
}
The error is still there.

Answer 1

The error regarding c_str has nothing to do with curl. Instead, it indicates you have not used C++ strings correctly. Reviewing the documents one can see that c_str is a method of the string object.
http://www.cplusplus.com/reference/string/string/c_str/
So, in all likelihood, you need to have something of the following form:
#include <string>
#include <curl/curl.h>
int main () {
std::string link ("http://www.example.com/foo1.jpg");
CURL curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, link.c_str());
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
}
}