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Provided Code

public class Book
{
    private String title;
    private double price;
    public Book(String bookTitle, double bookPrice) { /* not shown */ }
        public String getTitle() {
        return title;
    }
        public String getBookInfo() {
        return title + "-" + price;
    }
    // Other methods not shown.
}

// You will write the complete Textbook class (extends Book)
// A Textbook has: String title, double price (from Book) + int edition
// getBookInfo() returns "title-price-edition"
// canSubstituteFor(Textbook other) returns true if same title AND edition >= other's edition

Part A — 9 Points

Write the complete Textbook class. Must: extend Book, have a constructor with title/price/edition parameters calling super, include getEdition(), canSubstituteFor(Textbook), and override getBookInfo().

Write Your Solution

Check Answer Clear

public class Textbook extends Book
{
    private int edition;

    public Textbook(String title, double price, int edition)
    {
        super(title, price);
        this.edition = edition;
    }

    public int getEdition()
    {
        return edition;
    }

    public boolean canSubstituteFor(Textbook other)
    {
        return getTitle().equals(other.getTitle()) &&
               edition >= other.getEdition();
    }

    public String getBookInfo()
    {
        return super.getBookInfo() + "-" + edition;
    }
}

Common Mistakes to Avoid

public class Textbook

public class Textbook extends Book

public Textbook(String title, double price, int edition) {
    this.edition = edition;  // missing super() call!
}

public Textbook(String title, double price, int edition) {
    super(title, price);    // pass title and price to Book
    this.edition = edition;
}

return getTitle() == other.getTitle() && edition >= other.getEdition();

return getTitle().equals(other.getTitle()) && edition >= other.getEdition();

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