Dart1

void printer(num n, {String s1, String s2}){
  print(n);
  print(s1);
  print(s2);
}

main(){
  printer(1);
  printer(2, s1:"Hello");
  printer(3, s2:"Hi");
  printer(4, s1:"First", s2:"Second");
}
/////////////////////////////////////
void printer(num n,[String s1, String s2]){
  print(n);
  print(s1);
  print(s2);
}

main(){
  printer(1);
  printer(2,"Hello");
  printer(3,"Hi");
  printer(4,"First","Second");
}