#include <iostream>
#include <thread>
#include <mutex>

using namespace std ;

[[nodiscard]]
bool function1()
{
  return true;
}



int main()
{
	int x1 = 4 ;
	switch (x1)
	{
	  case 1:
		cout << "1" << endl ;
	    [[fallthrough]];
	  case 2:
		cout << "2" << endl ;
		break;
	  case 3:
		cout << "3" << endl ;
		[[fallthrough]];
	  default:
		cout << "4" << endl ;
	}

  //return value not used
  function1() ;


 [[maybe_unused]]
  bool error ;


    return 0;
}