Requesting beginner-level guidance with using libCurl API - c++

Question

I'm am trying to use libcurl (linked to a C++ program) for the first time, and need beginner-level help. I'm also largely unfamiliar with HTTP/HTML, etc. so please forgive me if my terminology belies that.
Using the executable curl, if I execute the following...
curl -k -u user:password https://confluence/pages/viewpage.action?pageId=42
...I get what looks like the legit contents of the webpage.
I would like to do the same from my C++ program using libcurl.
I've started with a minimal modification of basic example posted at https://curl.haxx.se/libcurl/c/simple.html:
#include <iostream>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl)
{
curl_easy_setopt(curl, CURLOPT_URL, "https://confluence/pages/viewpage.action?pageId=42");
res = curl_easy_perform(curl);
if(CURLE_OK == res) { std::cout << "curl success" << std::endl; }
else { std::cout << "curl failure" << std::endl; }
curl_easy_cleanup(curl);
}
return 0;
}
This code results in the output:
curl failure
Can anyone guide me on how I can programmatically do what I did earlier with the curl executable? There are some obvious deficiencies with my sample code, i.e. the absence of a username and password, so I'd appreciate any guidance in the right direction. Thank you.
Update
The reason I used the -k option when executing the curl executable was because running the command without -k resulted in no webpage content being returned by curl. I just tried adding -k based on the help text and observed it worked. Sorry for my lack of understanding and ability to explain. I'd be grateful if an answerer can touch on these topics too, to help me understand.
Update and Closure
I'm a little embarrassed that I turned to StackOverflow without a little bit more effort on my part - apologies to the community for this poor question.
The (insecure) solution, from just a bit of elbow-grease is:
#include <iostream>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl)
{
curl_easy_setopt(curl, CURLOPT_URL, "https://confluence/pages/viewpage.action?pageId=42");
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
res = curl_easy_perform(curl);
if(CURLE_OK == res) { std::cout << "curl success" << std::endl; }
else { std::cout << "curl failure" << std::endl; }
curl_easy_cleanup(curl);
}
return 0;
}

Answer 1

You are trying to access a secure website, it won't work unless you use secure socket(443) protocol.
Try using CURLOPT_USE_SSL e.g.
curl_easy_setopt(curl, CURLOPT_USE_SSL, "https://confluence/pages/viewpage.action?pageId=42");