The JavaTM Tutorial

| Start of Tutorial > Start of Trail > Start of Lesson | Search Feedback Form

Trail: Learning the Java Language
Lesson: Classes and Inheritance

## Answers to Questions and Exercises: Creating Classes

### Questions

> Question 1: Consider the following class:

> >     public class IdentifyMyParts {
> >         public static int x = 7;
> >         public int y = 3;
> >     }

> > a. How many class variables does the `IdentifyMyParts` class contain? What are their names?
> > Answer 1a: 1, x

> > b. How many instance variables does the `IdentifyMyParts` class contain? What are their names?
> > Answer 1b: 1, y

> > c. What is the output from the following code:

> > >     IdentifyMyParts a = new IdentifyMyParts();
> > >     IdentifyMyParts b = new IdentifyMyParts();
> > >     a.y = 5;
> > >     b.y = 6;
> > >     a.x = 1;
> > >     b.x = 2;
> > >     System.out.println("a.y = " + a.y);
> > >     System.out.println("b.y = " + b.y);
> > >     System.out.println("a.x = " + a.x);
> > >     System.out.println("b.x = " + b.x);

> > Answer 1c: Here is the output:

> > >      a.y = 5
> > >      b.y = 6
> > >      a.x = 2
> > >      b.x = 2

> ### Exercises

> > Exercise 1: Write a class whose instances represent a playing card from a deck of cards.
> > Answer 1: `Card.java`

> > Exercise 2: Write a class whose instances represents a deck of cards.
> > Answer 2: See `Deck.java`.

> > Exercise 3: Write a small program to test your deck and card classes. The program can be as simple as creating a deck of cards and displaying its cards.
> > Answer 3: See `DisplayDeck.java`.

| Start of Tutorial > Start of Trail > Start of Lesson | Search Feedback Form

Copyright 1995-2001 Sun Microsystems, Inc. All rights reserved.