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

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

  auto i = remove_if(begin(s), end(s), [](char c) { return c <'l'; });
  s.erase(i, end(s));  

  std::cout << s << '\n';
}