// Identidad (==) frente a igualdad (equals).
void main() {
    String s1 = "Lima";
    String s2 = "Lima";
    String part = "Li";
    String s3 = part + "ma";        // se arma mientras el programa corre

    IO.println("s1 == s2:      " + (s1 == s2));
    IO.println("s1 == s3:      " + (s1 == s3));
    IO.println("s1.equals(s3): " + s1.equals(s3));

    // Nuestra clase todavía no define equals: hereda el de Object, que usa ==.
    Thermometer t1 = new Thermometer("Lima", 18.0);
    Thermometer t2 = new Thermometer("Lima", 18.0);
    IO.println("t1 == t2:      " + (t1 == t2));
    IO.println("t1.equals(t2): " + t1.equals(t2));
}