Video Store Example

Programming in Java consists mostly of creating class hierarchies and instantiating objects from them. The Java Development Kit gives you a rich collection of base classes that you can extend to do your work.

Following is a program that uses a class Video to represent videos available at a store. Inheritance is not explicitly used in this program (so far).

Note to AP students: Study the toString() method and how it is used in main() to print a description of each object. This is a common technique. Several questions on AP-CS tests in the past few years have involved writing a toString() method for a class.

You can copy this program to an editor, save it, and run it.

class Video
{
  String  title;    // name of the item
  int     length;   // number of minutes
  boolean avail;    // is the video in the store?

  // constructor
  public Video( String ttl )
  {
    title = ttl; length = 90; avail = true; 
  }

  // constructor
  public Video( String ttl, int lngth )
  {
    title = ttl; length = lngth; avail = true; 
  }

  public String toString()
  {
    return title + ", " + length + " min. available:" + avail ;
  }
  
}

public class VideoStore
{
  public static void main ( String args[] )
  {
    Video item1 = new Video("Jaws", 120 );
    Video item2 = new Video("Star Wars" );

    System.out.println( item1.toString() );
    System.out.println( item2.toString() );     
  }
}

Answer:

Video Store Example

QUESTION 9: