[course06] homework

[course06] homework

Q1 Make a class

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.

Q2 restaurant table

The class SingleTable represents a table at a restaurant.

public class SingleTable {

/** Returns the number of seats at this table. The value is always greater than or equal to 4. */ 
public int getNumSeats() { 
    /* implementation not shown */ 
}

/** Returns the height of this table in centimeters. */ 
public int getHeight() { 
    /* implementation not shown */ 
}

/** Returns the quality of the view from this table. */ 
public double getViewQuality() { 
    /* implementation not shown */
}

/** Sets the quality of the view from this table to value . */ 
public void setViewQuality(double value) { 
    /* implementation not shown */ }

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

}

At the restaurant, customers can sit at tables that are composed of two single tables pushed together. You will write a class CombinedTable to represent the result of combining two SingleTable objects, based on the following rules and the examples in the chart that follows.

• A CombinedTable can seat a number of customers that is two fewer than the total number of seats in its two SingleTable objects (to account for seats lost when the tables are pushed together).

• A CombinedTable has a desirability that depends on the views and heights of the two single tables. If the two single tables of a CombinedTable object are the same height, the desirability of the CombinedTable object is the average of the view qualities of the two single tables.

• If the two single tables of a CombinedTable object are not the same height, the desirability of the CombinedTable object is 10 units less than the average of the view qualities of the two single tables.

Assume SingleTable objects t1, t2, and t3 have been created as follows.

• SingleTable t1 has 4 seats, a view quality of 60.0, and a height of 74 centimeters.

• SingleTable t2 has 8 seats, a view quality of 70.0, and a height of 74 centimeters.

• SingleTable t3 has 12 seats, a view quality of 75.0, and a height of 76 centimeters.

The chart contains a sample code execution sequence and the corresponding results.

The last line of the chart illustrates that when the characteristics of a SingleTable change, so do those of the CombinedTable that contains it.

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