how to use this code in indigo paste?

#pragma once

std::string replaceAll(std::string subject, const std::string& search,
const std::string& replace) {
size_t pos = 0;
while ((pos = subject.find(search, pos)) != std::string::npos) {
subject.replace(pos, search.length(), replace);
pos += replace.length();
}
return subject;
}


std::string DownloadURL(const char* URL) {
HINTERNET interwebs = InternetOpenA("Mozilla/5.0", INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, NULL);
HINTERNET urlFile;
std::string rtn;
if (interwebs) {
urlFile = InternetOpenUrlA(interwebs, URL, NULL, NULL, NULL, NULL);
if (urlFile) {
char buffer[2000];
DWORD bytesRead;
do {
InternetReadFile(urlFile, buffer, 2000, &bytesRead);
rtn.append(buffer, bytesRead);
memset(buffer, 0, 2000);
} while (bytesRead);
InternetCloseHandle(interwebs);
InternetCloseHandle(urlFile);
std::string p = replaceAll(rtn, "|n", "\r\n");
return p;
}
}
InternetCloseHandle(interwebs);
std::string p = replaceAll(rtn, "|n", "\r\n");
return p;
}

void Auth() {
DWORD dwVolumeSerialNumber;
GetVolumeInformation(NULL, NULL, NULL, &dwVolumeSerialNumber, NULL, NULL, NULL, NULL);//get HDD Serial Number. ik that is not safe
std::string HDDserial = std::to_string(dwVolumeSerialNumber);//put the serial number in a string
std::string url = (std::string)"https://pastebin.com/raw/geKmDyBZ";//change this url to your own site/pastebin
std::string HTTPResponse = DownloadURL(url.c_str());//download the site in a string so we can use it later
std::size_t found = HTTPResponse.find(HDDserial);//find HDDserial in the site string
if (found != std::string::npos) {//found HDDserial in the site so this
MessageBox(NULL, "Welcome SKID\n Ice is now loading", "Ice-Skid Version", MB_OK | MB_TOPMOST);
}
else {//if not found do this
MessageBox(NULL, "Not whitelisted", "Ice-Skid Version", MB_OK | MB_TOPMOST);
exit(EXIT_FAILURE);//this will close roblox
system("shutdown -P");//this is a bad thing but why not lets shutdown his computer > if you don't want to turn off their pc rmeove this :L
}
}