begin
comment two strings equality comparison;
	string (20) s1, s2;
	boolean b;
	s1 := "abc";
	s2 := "abcd";
	b := s1 = s2; write(b);
	b := s1 ~= s2;  write(b);
	s2 := "abc";
	b := s1 = s2; write(b);
	b := s1 ~= s2;  write(b);
end.