// to represent a book
public class Book implements ISame{
	String	title;
	String	author;
	int	year;
	
	public Book(String title, String author, int year){
		this.title = title;
		this.author = author;
		this.year = year;
	}
	
	// was this book published before the given year
	public boolean before(int year){
		return this.year < year;
	}
	
	// determine extensional equality of this and given object
	public boolean same(Object obj){
		return this.title.equals(((Book)obj).title)
		    && this.author.equals(((Book)obj).author)
			&& this.year == ((Book)obj).year;
	}
	
	// provide the values of this instance represented as a String
	public String toString(){
		return "\n Book: " + 
		       "\n title: "  + this.title +
			   "\n author: " + this.author +
			   "\n year: "   + this.year + "\n";
	}
	

}