2022 Free Response

This question involves simulation of the play and scoring of a single-player video game. In the game, a player attempts to complete three levels.

A level in the game is represented by the Level class.

public class Level
{
    /** Returns true if the player reached the goal on this level and returns false otherwise */
    public boolean goalReached()
    {  /* implementation not shown */  }

    /** Returns the number of points (a positive integer) recorded for this level */
    public int getPoints()
    {  /* implementation not shown */  }

    // There may be instance variables, constructors, and methods that are not shown.
}

Play of the game is represented by the Game class. You will write two methods of the Game class.

public class Game
{
    private Level levelOne;
    private Level levelTwo;
    private Level levelThree;

    /** Postcondition: All instance variables have been initialized. */
    public Game()
    {  /* implementation not shown */  }

    /** Returns true if this game is a bonus game and returns false otherwise */
    public boolean isBonus()
    {  /* implementation not shown */  }

    /** Simulates the play of this Game (consisting of three levels) and updates all relevant
     *  game data
     */
    public void play()
    {  /* implementation not shown */  }

    /** Returns the score earned in the most recently played game, as described in part (a) */
    public int getScore()
    {  /* to be implemented in part (a) */  }

    /** Simulates the play of num games and returns the highest scored earned, as
     *  described in part (b)
     *  Precondition: num > 0
     */
    public int playManyTimes(int num)
    {  /* to be implemented in part (b) */  }

    // There may be instance variables, constructors, and methods that are not shown.
}

The following table shows some examples of game score calculations.

[Table columns are headed "goalReached Return Value:", "getPoints Return Value:", "isBonus Return Value", and "Score Calculation"; each data row shows the Level One/Level Two/Level Three values stacked in the goalReached and getPoints columns.]

Class information for this question:

public class Level
public boolean goalReached()
public int getPoints()

public class Game
private Level levelOne
private Level levelTwo
private Level levelThree
public Game()
public boolean isBonus()
public void play()
public int getScore()
public int playManyTimes(int num)

The Book class is used to store information about a book. A partial Book class definition is shown.

public class Book
{
    /** The title of the book */
    private String title;

    /** The price of the book */
    private double price;

    /** Creates a new Book with given title and price */
    public Book(String bookTitle, double bookPrice)
    {  /* implementation not shown */  }

    /** Returns the title of the book */
    public String getTitle()
    {  return title;  }

    /** Returns a string containing the title and price of the Book */
    public String getBookInfo()
    {
        return title + "-" + price;
    }

    // There may be instance variables, constructors, and methods that are not shown.
}

You will write a class Textbook, which is a subclass of Book.

A Textbook has an edition number, which is a positive integer used to identify different versions of the book. The getBookInfo method, when called on a Textbook, returns a string that also includes the edition information, as shown in the example.

Information about the book title and price must be maintained in the Book class. Information about the edition must be maintained in the Textbook class.

The Textbook class contains an additional method, canSubstituteFor, which returns true if a Textbook is a valid substitute for another Textbook and returns false otherwise. The current Textbook is a valid substitute for the Textbook referenced by the parameter of the canSubstituteFor method if the two Textbook objects have the same title and if the edition of the current Textbook is greater than or equal to the edition of the parameter.

The following table contains a sample code execution sequence and the corresponding results. The code execution sequence appears in a class other than Book or Textbook.

Write the complete Textbook class. Your implementation must meet all specifications and conform to the examples shown in the preceding table.

Users of a website are asked to provide a review of the website at the end of each visit. Each review, represented by an object of the Review class, consists of an integer indicating the user's rating of the website and an optional String comment field. The comment field in a Review object ends with a period ("."), exclamation point ("!"), or letter, or is a String of length $0$ if the user did not enter a comment.

public class Review
{
    private int rating;
    private String comment;

    /** Precondition: r >= 0
     *      c is not null.
     */
    public Review(int r, String c)
    {
        rating = r;
        comment = c;
    }

    public int getRating()
    {
        return rating;
    }

    public String getComment()
    {
        return comment;
    }

    // There may be instance variables, constructors, and methods that are not shown.
}

The ReviewAnalysis class contains methods used to analyze the reviews provided by users. You will write two methods of the ReviewAnalysis class.

public class ReviewAnalysis
{
    /** All user reviews to be included in this analysis */
    private Review[] allReviews;

    /** Initializes allReviews to contain all the Review objects to be analyzed */
    public ReviewAnalysis()
    {  /* implementation not shown */  }

    /** Returns a double representing the average rating of all the Review objects to be
     *  analyzed, as described in part (a)
     *  Precondition: allReviews contains at least one Review.
     *      No element of allReviews is null.
     */
    public double getAverageRating()
    {  /* to be implemented in part (a) */  }

    /** Returns an ArrayList of String objects containing formatted versions of
     *  selected user comments, as described in part (b)
     *  Precondition: allReviews contains at least one Review.
     *      No element of allReviews is null.
     *  Postcondition: allReviews is unchanged.
     */
    public ArrayList<String> collectComments()
    {  /* to be implemented in part (b) */  }
}

Class information for this question:

public class Review
private int rating
private String comment
public Review(int r, String c)
public int getRating()
public String getComment()

public class ReviewAnalysis
private Review[] allReviews
public ReviewAnalysis()
public double getAverageRating()
public ArrayList<String> collectComments()

This question involves a two-dimensional array of integers that represents a collection of randomly generated data. A partial declaration of the Data class is shown. You will write two methods of the Data class.

public class Data
{
    public static final int MAX = /* value not shown */;
    private int[][] grid;

    /** Fills all elements of grid with randomly generated values, as described in part (a)
     *  Precondition: grid is not null.
     *      grid has at least one element.
     */
    public void repopulate()
    {  /* to be implemented in part (a) */  }

    /** Returns the number of columns in grid that are in increasing order, as described
     *  in part (b)
     *  Precondition: grid is not null.
     *      grid has at least one element.
     */
    public int countIncreasingCols()
    {  /* to be implemented in part (b) */  }

    // There may be instance variables, constructors, and methods that are not shown.
}

Class information for this question:

public static final int MAX = /* value not shown */
private int[][] grid
public void repopulate()
public int countIncreasingCols()