this is the past year question and the answer. have fun!
QUESTION 5 (APRIL 2008)
Given the following program
segment:
public class Land
{ protected String owner;
protected double area;
abstract double calcTax();
abstract void display();
public Land( String own, double
area)
{
//method definition
}
}
public class Housing extends Land
{
private char houseType;
private double tax_rate;
public Housing(String
own,double area,char Hsetype)
{
//method definition
}
public double calcTax()
{
//method definition
}
public void display()
{
//method definition
}
}
public class Agriculture extends Land
{
private double fixed_tax_rate =
3.00;
public Agriculture(String
own,double area)
{
//method definition
}
public double calcTax()
{
//method definition
}
public void display()
{
//method definition
} }
a) Define the method calcTax()of class Housing based on the
following:
The tax for this type
of land depends on its area and the type of house built on the land:
|
House Type
|
Description
|
Tax Rate (RM/m2)
|
|
T
|
Terrace
|
10
|
|
S
|
Semi-Detached
|
15
|
|
B
|
Bungalow
|
20
|
|
C
|
Condominium
|
5
|
(4 marks)
b) Define method calcTax()of class Agriculture. Agricultural lands are all charged a fixed rate of
RM 3 per meter square (m2).
(2 marks)
b)
Write an application program that uses the concept of
polymorphism to
i. store data on various
types of land. The number of data to be stored and information on each land are
given by the user. The input process stops when the users key-in a sentinel
value.
ii. Display the total Tax for all lands.
iii. Display the Tax amount
for Housing lands only.
iv. Determine and display the highest tax for
Agriculture land.
(12
marks)
APRIL 2008
a)
Answer:
public double calcTax()
{
double tax=0.0;
->0.5 mark
if (houseType == 'T')
{
tax_rate = 5;
tax = area * tax_rate;
} ->0.5 mark
else if (houseType == 'S')
{
tax_rate = 10;
tax = area * tax_rate;
} -> 0.5 mark
else if (houseType == 'B')
{
tax_rate = 15;
tax = area * tax_rate;
} ->0.5 mark
else if (houseType == 'C')
{
tax_rate = 20;
tax = area * tax_rate;
}
-> 0.5 mark
return tax;
-> 0.5 mark
}note : 1 mark if program
correct
b) Answer:
private double fixed_tax_rate = 3.00;
->0.5 mark
public double calcTax()
{
double tax = fixed_tax_rate * area; -> 1 mark
return tax; -> 0.5 mark }
c) Answer:
public class TestLand
{
static Scanner console = new
Scanner(System.in);
public static void main(String[] args)
{
String
owner,type;
double
area;
char
hsetype;
double
taxRate;
char
input = 'Y';
int
count =0;
Land[]
L = new Land[20];
while(input != 'N')
{
System.out.print("Enter the land owner
: ");
owner = console.next();
System.out.print("\nEnter the land area
: ");
area
= console.nextDouble();
System.out.print("Enter the land type:
H-Housing,A-
Agriculture ");
type = console.next();
switch(type.charAt(0))
{
case 'H' : System.out.println("Enter house type :
");
hsetype =
console.next().charAt(0);
//taxRate =
console.nextDouble();
L[count] = new
Housing(owner,area,hsetype);
break;
case 'A' : L[count] = new Agriculture(owner,area);
break;
default : System.out.println( "Wrong land
type");
}
count++;
System.out.println("Do you want to
continue ?(Y or N) : ");
input = console.next().charAt(0);
}
System.out.println("length
="+L.length);
for(int k=0; k<count;k++)
{
L[k].Display();
}
System.out.println("Count
="+count);
double totalTax=0.0;
for(int k=0; k<count;k++)
{
totalTax = totalTax + L[k].calcTax();
}
System.out.println("Total tax =
"+totalTax);
for (int k=0; k < count; k++)
{
if (L[k] instanceof
Housing)
{
System.out.print("Tax amount for
Housing land = ");
System.out.println(L[k].calcTax());
}
}
double highest = 0.0;
for (int k=0; k <
count; k++)
{
if (L[k] instanceof
Agriculture)
if (L[k].calcTax()
> highest)
highest =
L[k].calcTax();
}
System.out.println("Highest
tax for agriculture land = "+highest);
}
QUESTION 3 (APRIL
2009)
Given
the following inheritance hierarchy
And
the definition for the BankAccount
class:
abstract class BankAccount
{
private
String name;
private
long accNum;
private
double balance;
public BankAccount() {}
public BankAccount(String name, long accNum, double balance)
{ //method definition}
public
String getName()
{ //method definition }
public long
getAcc()
{ //method definition }
public double
getBalance()
{ //method definition }
public String
toString()
{ //method definition }
//method to update
the balance for the account
public abstract
double updateBalance();
}
a) Define the Saving class
that inherits from the BankAccount class. The attributes and methods are as
follows:
Attributes: interest rate
Methods:
·
Constructor
with arguments
·
toString(),
to return the string
representation of the object
·
updateBalance(),
given the formulae:
update = (interest rate X balance) +
balance;
(10 marks)
b) Define the Current class
that inherits from the BankAccount class. The attributes and methods are as
follows:
Attributes: interest rate and transaction
fee
Methods:
·
Constructor
with arguments
·
toString(),
to return the string
representation of the object
·
updateBalance(),
given the formulae:
update = (interest rate X balance) + balance
– transaction fee;
(10 marks)
c) Write a Java application class called BankApp that uses the concept of polymorphism to perform the following tasks:
·
Declare
an array of objects to store data on various types of BankAccount.
·
Display
the details for all bank customers.
·
Display
the details of customer whose balance exceeding RM 100,000
·
Calculate
and display the total balance of all Saving accounts and total balance of all Current accounts.
.(15 marks)
APRIL 2009
a)
public
class Saving extends BankAccount
{
private
double rate;
public Saving(String name, long accNum,
double balance,
double rate)
{
super(name, accNum, balance);
this.rate = rate;
}
public String toString()
{
return
super.toString() + " Interest rate: " + rate;
}
public double updateBalance()
{
double
update = (rate * super.getBalance()) +
super.getBalance();
return update;
}
}
b) public
class Current extends BankAccount
{
private double rate;
private double fee;
public Current(String name, long accNum,
double balance,
double
rate, double fee)
{
super(name, accNum, balance);
this.rate = rate;
this.fee = fee;
}
public
String toString()
{ return super.toString() + " Interest
rate: " + rate + " Fee:"
+ fee;
}
public double updateBalance()
{
double update = (rate *
super.getBalance()) +
super.getBalance() - fee;
return update;
}
}
c)
import javax.swing.*;
public
class BankApp
{
public static void main(String args[])
{
int n =
Integer.parseInt(JOptionPane.showInputDialog(" Number
of
customers: "));
BankAccount[]
acct = new BankAccount[n];
for(int i = 0; i < acct.length; i++)
{
String
nm = JOptionPane.showInputDialog("Customer's Name: ");
long
accNo = Long.parseLong(JOptionPane.showInputDialog
("
Account #: "));
double
bal = Double.parseDouble(JOptionPane.showInputDialog
("
Balance: "));
String type =
JOptionPane.showInputDialog("Type - (S)aving/"
+ "(C)hecking ");
char
accType = type.toUpperCase().charAt(0);
if (accType == 'S')
{
double rt =
Double.parseDouble(JOptionPane.showInputDialog
("
Interest rate: "));
acct[i] = new Saving(nm, accNo, bal,
rt);
}
if (accType == 'C')
{
double irate = Double.parseDouble
(JOptionPane.showInputDialog (" Interest
rate: "));
double tfee =
Double.parseDouble(JOptionPane.showInputDialog
(" Transaction fee: "));
acct[i] = new Current(nm, accNo, bal,
irate, tfee);
}
}
for (int i = 0; i < acct.length; i++)
{
System.out.println(" The details
of customers : " +
acct[i].toString());
if (acct[i].updateBalance() > 100000)
System.out.println(" The customers
with balance > 100000:"
+
acct[i].toString());
}
double saveBalance = 0, currBalance = 0;
for(int i = 0; i < acct.length; i++)
{
if(acct[i] instanceof Saving)
saveBalance +=
acct[i].updateBalance();
if(acct[i] instanceof Current)
currBalance +=
acct[i].updateBalance();
}
System.out.println(" Total Balance
for Saving account: " +
saveBalance);
System.out.println(" Total Balance
for Current account: " +
currBalance);
}
}
QUESTION 3 (NOV
2009)
Given
the following definition
public abstract class Student
{
private String name;
private double test1;
private double test2;
private double test3;
protected char grade;
public
Student(String n, double tl, double t2, double t3)
{ . . . }
public abstract char
computeGrade();
// Accessors
public String
getName() {...}
public double
getTest1() {...}
public double
getTest2() {...}
public double
getTest3() {...}
public char getGrade
(){...}
public String toString
(){...}
}
Suppose
Undergraduate and Graduate extends Students, with no additional attributes.
Using polymorphism, write a Java application to
a. get
the number of students and necessary data from the user. Store these data into
an array of students
b. calculate
and display the total number of students who get grade A and count how many of
these students from each subclass, Undergraduate and Graduate.
c. Find
and display the information of student whose name is given by the user
(4 mark)
QUESTION 3 (Nov 2009)
import javax.swing.*;
public class StudentApp
{
public static void main(String args[])
{
int n =
Integer.parseInt(JOptionPane.showInputDialog
("
Number of Students: "));
Student[] stu = new Student[n];
int under = grad = 0;
for(int
i = 0; i < acct.length; i++)
{
String nm =
JOptionPane.showInputDialog("Student's Name: ");
double t1 =
Double.parseDouble(JOptionPane.showInputDialog
("
Test 1: "));
double t2 =
Double.parseDouble(JOptionPane.showInputDialog
("
Test 2: "));
double t3 =
Double.parseDouble(JOptionPane.showInputDialog
("
Test 3: "));
String type = JOptionPane.showInputDialog
("Type
- (U)ndergraduate/" + "(G)raduate ");
char stuType = type.toUpperCase().charAt(0);
if
(stuType == 'U')
{
stu[i] = new Undergraduate(nm, t1, t2, t3);
}
if
(stuType == 'G')
{
stu[i] = new Undergraduate(nm, t1, t2, t3);
} }
for (int i = 0; i <
stu.length; i++)
{
if( stu[i].getGrade() == ‘A’)
{
if(stu[i] instanceof Undergraduate)
under++;
if(stu[i] instanceof Graduate)
grad++;
}
}
System.out.println(" Total A student
from Undergraduate: " +
under);
System.out.println(" Total A student
from Graduate: " + grad);
String input = JOptionPane.showInputDialog
("Search
Student's Name: ");
for (int i = 0; i < stu.length; i++)
{
if(input.equalsIgnoreCase(stu[i].getName())
System.out.println(“Found
“ + stu[i].toString());
} } }
QUESTION 4 (NOV
2009)
Given
the following inheritance hierarchy
and the list of
data members and methods for ThemePark, WaterPark, and WildlifePark classes:
Superclass : abstract class
ThemePark
Data member(s):
String name; //
customer's name
String icNo; // customer's identification card number
boolean member; // either member or not member of the park
Methods:
ThemePark();
ThemePark(String
name, String icNo, boolean member);
String
getName(); // return the customer's
name
String
getlc(); // return the ic number
boolean
getMember(); // return the membership
String
toString(); // return the details of
objects
abstract
double calCharges(); // calculate the charges
Subclass
:
class
WaterPark
Data member(s):
boolean surfBeach; // either true or false
to surf
boolean waterRides; // either true or false
to ride
Methods:
boolean
getSurf();// return the surfing status
boolean
getRide();// return the riding status
double
calCharges();// calculate the charges
String
toString();// return the details of objects
Subclass
:
class
WildlifePark
Data member(s):
String
category; // category of the customers
Methods:
String
getCategory();// return the category
double
calCharges();// calculate the charges
a) Write the normal
constructors for superclass and both subclasses.
(6 marks)
b) Given the details of ticket
charges in table 5.1 and table 5.2 for both Water and Wildlife Parks below:
|
Activity
|
Cost(RM)
|
|
Surf Beach
|
25.00
|
|
Water Rides
|
20.00
|
Table 5.1 Details of ticket charges for Water Park
|
Category
|
Cost(RM)
|
|
Adult
|
35.00
|
|
Child
|
20.00
|
Table 5.2 Details of ticket charges for Wildlife Park
Write abstract methods named calcharges() to calculate the charges of the activities
for both WaterPark and WildlifePark classes. The
customers who are the members of the theme park will be given a special
discount of 25% for every total charges.
(9 marks)
QUESTION 4 (Nov 2009)
a)
public ThemePark(String name, String ic,
boolean member)
{
this.name = name;
this.icNo = ic;
this.member = member;
}
public
WaterPark(String name, String ic, boolean member, boolean surf,
boolean ride)
{
super(name, ic, member);
this.surfBeach = surf;
this.waterRides = ride;
}
public
WildlifePark(String name, String ic, boolean member,
String
category)
{
super(name, ic, member);
this.category = category;
}
b)
public double calCharges() // waterpark
{
double total = 0;
if( getSurf() == true)
total = total + 25;
if(getRide == true)
total = total + 20;
if(getMember() == true)
total = total – (total * 0.25);
return total;
}
public double calCharges() // wildlifepark
{
double total = 0;
if( getCategory().equalsIgnoreCase(“Adult”))
total = total + 35;
else if(getCategory().equalsIgnoreCase(“Child”))
total = total + 20.00;
if(getMember() == true)
total = total – (total * 0.25);
return total;
}
