The code for the Book class
public class Book extends Product
{
     private String author;

     public Book()
     {
           super();
           author = "";
           count++;
     }
     public void setAuthor(String author)
     {
           this.author = author;
     }  
     public String getAuthor()
     {
           return author;
     }
     public String toString()
     {
           return super.toString() +
                "Author:     " + author + "\n";
     }
}

The code for Software class

public class software extends Product
{
     private String version;

     public Software()
     {
           super();     // call constructor of Product superclass
           version = "";
           count++;     // update the count variable in the Product superclass 
     } 
     public void setVersion(String version)
     {
           this.version = version;
     }
     public String getVersion()
     {
           return version;
     }
     public String toString()   // override the toString method
     {
           return super.toString() +   
               "Vesion:      " + version + "\n";
     }
}