Question

A library issues books on rental basis at a 2% charge on the cost price of the book per day. As per the rules of the library, a book can be retained for 7 days without any fine. If the book is returned after 7 days, a fine will also be charged for the excess days as per the chart given below:

Number of excess days	Fine per day (Rs.)
1 to 5	2.00
6 to 10	3.00
Above 10	5.00

A super class Library has been defined. Define a sub class Compute to calculate the fine and the total amount. The details of the members of both the classes are given below:

Class name	Library
Data members/instance variables:
name	to store the name of the book
author	to store the author of the book
p	to store the price of the book (in decimals)
Methods / Member functions:
Library(... )	parameterized constructor to assign values to the data members
void show( )	displays the book details
Class name	Compute
Data members/instance variables:
d	number of days taken in returning the book
f	to store the fine (in decimals)
Methods / Member functions:
Compute(...)	parameterized constructor to assign values to the data members of both the classes
void fine( )	calculates the fine for the excess days as given in the table above
void show()	displays the book details along with the number of days, fine and the total amount to be paid. Total amount is (2% of price of book * total no of days) + fine

Assume that the super class Library has been defined. Using the concepts of Inheritance, specify the class Compute giving the details of constructor, void fine ( ) and void show ( ) functions.

The super class, main function and algorithm need NOT be written.

Answer 1

class Compute extends Library
{
   private int d;
   private double f;
   public Compute(String name, String author, double p, int d)
   {
     super(name, author,p);
     this.d=d;
     f=0.0;
   }
   public void fine()
   {
     int d1=d-7;
     if(d1>=1 && d1<=5)
       f=d1*2;
     else if(d1>=6 && d1<=10)
       f=d1*3;
     else
       f=d1*5;
   }
   public void show()
   {
       super.show();
       System.out.println("Fine=" +f);
       System.out.println("Total amount="+ ((0.02*p*d)+f));
   }
}