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Program listing

// Copyright (C) 1998-2016 Davin Pearson
// Website:

class Person
   // Properties of the class...
   private String name;
   private int    age;

   // Constructor of the class...
   public Person(String aName, int anAge)
      name = aName;
      age  = anAge;

   // Methods of the class...
   public void talk()
      System.out.println("Hi, my name's " + name);
      System.out.println("and my age is " + age);
   public void commentAboutAge()
      if (age < 5)
      if (age == 5)
         System.out.println("time to start school");

class PersonTest
   // The main method is the point of entry into the program...
   public static void main(String[] args)
      Person ls = new Person("Luke Skywalker",34);
      Person wp = new Person("Winston Peters",48);;;


// (1) Think of a new property that a person can have and add
// it to the Person class.  You should be able to do this
// by copying the pattern of the other properties of the
// Person class.  Four changes to the program listing are
// needed:

// (1a) Add the name of the property and its type to the
// "properties" section of the class.
// (1b) Add an extra parameter to the the constructor so
// that the property gets initialised correctly.
// (1c) Modify the main method so that the Luke Skywalker
// and Winston Peters objects get the appropriate value of
// the new property.
// (1d) Modify the talk method so that the new property is
// printed to the screen when the talk method is called.
// (2) Modify the commentAboutAge method to print the
// message "old person" if the person's age is greater
// than 40.
// (3) In the main method add two calls to commentAboutAge,
// one for Luke Skywalker and one for Winston Peters.
// (4) Write a method growOlder that adds one year to the
// person's age.  Make Winston Peters get older by one year
// by putting a call in the main method to do this.

// HINT: Look at the talk and the commentAboutAge methods to
// see how to define a method.
// (5) Write a method giveKnighthood that adds the word
// "Sir" to the beginning of a person's name.  Then make
// Winston Peters become "Sir Winston Peters" by calling
// this method from the main method.

// HINT: This is much like question (4), except you are
// adding strings instead of numbers.
// (6) How is it possible to print the value of Luke
// Skywalker's age directly from inside the main method
// without calling the talk method?

// HINT: The talk method has a line of code to print the
// person's age.  Copy this code to the main method, but
// since you are in another class from the age property, you
// will need to mention the name of the object in front of
// the age property, so age becomes ls.age.

// Also, you will need to change the definition of the age
// property from private to public to get this change to
// work.  Why you need to do this will be covered in more
// detail in another tutorial.
// (7) Delete the calls to commentAboutAge that you added in
// question (3), and instead put a call to commentAboutAge
// in the talk method.  Note that when you are calling a
// method of the same class you are in, you don't have to
// put the object name in front of the method.

// Your program should generate similar output to what it
// did before.
// (8) Write a growOlderBy method which is similar to the
// growOlder method, except that it has an int parameter
// called years which says how many years the person should
// grow older by.  In the main method, place a call to
// growOlderBy to make Luke Skywalker age by ten years.