Friday's class example

Runner.java

import java.util.ArrayList;

public class Runner {
	public static void main(String[] args) {
		Person msM = new Teacher("Ms.", "M");
		ArrayList<Person> people = new ArrayList<Person>();
		people.add(msM);
		
		msM.getName();
		((Teacher) msM).assignHomework();
		
		// Dynamic typing.
		Person anything;
		if (Math.random() < .5) {
			anything = new Teacher("Ms", "X");
		} else {
			anything = new Student("Foo");
		}
		
		Teacher msC = new Teacher("Mrs", "C");
		msC.getName();
		msC.assignHomework();
		
		// Downcasting.
		Person offDuty = msC;
		
		System.out.println(msC.getName());
		Person p = new Person("blah");
		System.out.println(p.getName());
		
		// Method overloading.
		addStuff(3, 4);
		addStuff(1,"s");
		
		Person p2 = people.get(0);
		p2.getName();
	}

	public static void addStuff(int x, int y) {
		System.out.println(x+y);
	}

	public static void addStuff(int x, String z) {
		System.out.println(x+z);
	}
}

class Person {
	
	String name;
	
	Person(String inputName) {
		name = inputName;
	}
	
	public String getName() {
		return name;
	}
}

class Teacher extends Person {
	
	String title;
	Teacher(String inputTitle, String inputName) {
		super(inputName);
		title = inputTitle;
	}
	
	public void assignHomework() {
		
	}
	
	// Method overriding.
	public String getName() {
		return title +". "+ super.getName();
	}
}

class Student extends Person {
	
	// Constructor.
	Student(String inputName) {
		super(inputName);
	}

	// Non-constructor method.
	public void doHomework() {
		
	}
}