#include <algorithm>
#include <functional>
#include <iterator>
#include <string>
#include <iostream>

int main()
{
  std::string s = "Hallo, Welt";
  std::string t;
  std::cout << s << '\n';

  std::remove_copy_if(begin(s), end(s),
                      std::back_inserter(t), [](char c) { return c < 'l'; });

  std::cout << t << '\n';
  return 0;
}