#include <algorithm>
#include <iostream>
#include <string>

int main()
{
  std::string s = "Hallo Welt";
  std::string sequence = "ALL";
  std::cout << s << '\n';

  auto pos = std::search(begin(s), end(s), begin(sequence), end(sequence),
      [](char a, char b) { return std::tolower(a) == std::tolower(b); } // ignore case   
    );

  std::cout << " " << std::string(pos, end(s)) << '\n'
            << " " << sequence << '\n';
}