public class PersonStudentTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Person  p = new Person(24, "Thien");
		p.speak();
		Student s = new Student(28, "Stefani", 3.8);
		s.speak();
		p = s; // OK, since a student is a person
		// s = p; // NO, since a person is not a student
		p.speak();
		
		// Group of persons
		Person[] person = new Person[4];
		String[] name = {"Aaron", "Kallista", "Hieu", "Joe"};
		for (int i =0; i < person.length; i ++) {
			int age = 20 + (int) (Math.random() * 30);
			if (Math.random() < 0.5) { // person
				person[i] = new Person(age, name[i]	);
			}
			else { // student
				person[i] = new Student(age, name[i], Math.random()  + 3);
			}
		}
		
		// Make the group of persons speak
		for (int i = 0; i < person.length; i ++) {
			person[i].speak();
		}
	}

}