The document provides instructions to create classes for Person, Customer, Employee, FullTimeEmployee, and PartTimeEmployee with various attributes and methods. It then provides data to create objects of these classes and assign them to arrays, and calls methods to calculate values like profit, salary, tax, and averages. The goal is to model these business entities and their relationships using object-oriented programming principles in Java.

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Object Oriented Programming Assignment 4
Author: Kasun Ranga Wijeweera
Email: krw19870829@gmail.com
Date: 2019 October 25
1) Suppose you have to develop an information system for a company. A part of the class
diagram is given below.
a) Create the class Person that includes attributes: id, name, age, and gender with data
types: “int”, “String”, “int”, and “char” respectively.
b) Include a constructor to the class Person with parameters: id, name, age, and gender.
c) Include getters and setters for each attribute of the class Person.
d) Include a method called display to the class Person to display the values of attributes of
the class.
e) Include a method called getAverageAge to the class Person to get the average age of a
person.
f) Create the class Customer that includes attributes: level, amount1, amount2, and profit
with data types: “int”, “double”, “double”, and “double” respectively.
g) Include a constructor to the class Customer with parameters: id, name, age, gender, and
level.
h) Include getters and setters for each attribute of the class Customer.
i) Include a method called display to the class Customer to display the values of attributes
of the class.
Person
Customer Employee
FullTimeEmployee PartTimeEmployee

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j) Consider the class Customer. The value of the attribute profit is computed by
subtracting the value of the attribute amount1 from the value of the attribute amount2.
Include a method called calculateProfit to the class to calculate the value of the attribute
profit.
k) Include a method called buyItems to the class Customer with parameters: price1,
price2, and n. The new value of the attribute amount1 is computed by multiplying the
value of the attribute price1 with the value of the attribute n and adding the value of the
attribute amount1. The value of the attribute amount2 is computed by multiplying the
value of the attribute price2 with the value of the attribute n and adding the value of the
attribute amount2. Include these computations to the body of the method.
l) Include a method called reduceProfit to the class Customer that computes the value of
reduction. The value of reduction is computed by multiplying the value of attribute profit
from the value of t. The value of t is based on the value of the attribute level as given in
the table below. Furthermore, the value of reduction should be subtracted from the value
of attribute profit.
level t
1 0.03
2 0.05
3 0.08
4 0.12
m) Create the driver class called Test that includes the “main” method.
n) Include a class method called display to the class Test that takes an array of references of
type Person as the parameter. The method should display the values of attributes of the
objects referred through the parameter.
o) Create an array that holds five Customer objects. Assign the objects given in the table
below to each array element using the constructor.
id name age gender level
3521 Kasun 27 M 3
4863 Nimal 23 M 2
5791 Nayana 28 F 4
2456 Chathura 32 M 1
7593 Waruni 18 F 2
p) Use the method display in the class Test to display the values of attributes of the
Customer objects.
q) Increment the value of the attribute level of the fourth Customer object by 1.

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r) Change the value of the attribute gender of the third Customer object to „M‟.
s) Use the method display in the class Customer to display the values of attributes of
second and third Customer objects.
t) Use the method getAverageAge in the class Person to compute the average age of the
Customer objects.
u) The table given below shows the set of items bought by each of the customer. Use the
method buyItems in the class Customer to add the given items.
id price1 price2 n
3521 54 57 8
32 39 5
75 76 7
4863 45 48 9
78 81 12
12 14 17
24 27 4
5791 92 96 8
125 130 10
2456 82 89 7
138 155 6
52 60 2
66 75 11
105 120 21
7593 99 110 2
v) Use the method calculateProfit in the class Customer to compute the value of the
attribute profit of each Customer object.
w) Display the value of the attribute profit of each Customer object.
x) Compute the new value of the attribute profit of each Customer object using the method
reduceProfit in the class Customer.
y) Create the class Employee that includes attributes: designation, mobile, salary and tax
with data types: “String”, “String”, “double” and “double” respectively.
z) Include a constructor to the class Employee with parameters: id, name, age, gender,
designation, and mobile.
aa) Include getters and setters for each attribute of the class Employee.

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bb) Include a method called display to the class Employee to display the values of attributes
of the class.
cc) Include a method called getAverageSalary to the class Employee to get the average
salary of an employee.
dd) Include a method called computeTax to the class Employee with the parameter taxRate
to compute the value of the attribute tax. The value of the attribute tax is computed by
multiplying the value of the attribute salary with the value of the attribute taxRate.
ee) Include a method called getNetSalary to the class Employee. The method should return
the value that is computed by subtracting the value of the attribute tax from the value of
the attribute salary.
ff) Create the class FullTimeEmployee that includes attributes: fund and fundRate with
data types: “double” and “double” respectively.
gg) Include a constructor to the class FullTimeEmployee with parameters: id, name, age,
gender, designation, mobile, and fundRate. The value of the attribute fund should be
initially zero for any full-time employee.
hh) Include getters and setters for each attribute of the class FullTimeEmployee.
ii) Include a method called display to the class FullTimeEmployee to display the values of
attributes of the class.
jj) Include a method called addToFund to the class FullTimeEmployee to add an amount
to the value of the attribute fund. The amount to be added is computed by multiplying the
value of the attribute salary with the value of the attribute fundRate. The value of the
attribute fund should be subtracted from the value of the attribute salary.
kk) Create an array that holds seven FullTimeEmployee objects. Assign the objects given in
the table below to each array element using the constructor.
id name age gender designation mobile fundRate
68494 Nuwan 52 M Manager 0516859465 3%
98451 Charaka 29 M Assistant Manager 0919576348 2%
79563 Wathsala 34 F Clerk 0668567956 1%
36864 Chathurika 35 F Clerk 0219762354 2%
48952 Sandun 27 M Laborer 0319548261 1%
65825 Janith 21 M Laborer 0119652352 0.5%
56286 Chamari 38 F Clerk 0512648927 2%

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ll) Use the method display in the class Test to display the values of attributes of the
FullTimeEmployee objects.
mm) Set the value of the attribute salary of each FullTimeEmployee object according
to the table given below.
id salary
68494 65000
98451 60000
79563 35000
36864 30000
48952 20000
65825 25000
56286 40000
nn) Invoke the method addToFund in the class FullTimeEmployee for each
FullTimeEmployee object. The value of the parameter fundRate is computed according
to the table given below.
id fundRate
68494 4%
98451 3%
79563 2%
36864 1%
48952 2%
65825 2%
56286 1%
oo) Create the class PartTimeEmployee that includes attributes: hours and rate with data
types: “double” and “double” respectively.
pp) Include a constructor to the class PartTimeEmployee with parameters: id, name, age,
gender, designation, mobile, and rate.
qq) Include getters and setters for each attribute of the class PartTimeEmployee.
rr) Include a method called display to the class PartTimeEmployee to display the values of
attributes of the class.
ss) Include a method called computeSalary to the class PartTimeEmployee to compute the
value of the attribute salary. The value of the attribute salary is computed by multiplying
the value of the attribute hours with the value of the attribute rate.

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tt) Create an array that holds two PartTimeEmployee objects. Assign the objects given in
the table below to each array element using the constructor.
id name age gender designation mobile rate
68542 Saman 56 M Temporary Clerk 0215698542 300
79546 Nimal 57 M Temporary Laborer 081684952 150
uu) Set the value of the attribute hours of each PartTimeEmployee object according to the
table given below.
id hours
68542 160
79546 172
vv) Compute the value of the attribute salary of each PartTimeEmployee object by
invoking the method computeSalary in the class PartTimeEmployee.
ww) Create an array of type Employee that has nine elements. Assign the seven
FullTimeEmployee objects and the two PartTimeEmployee objects you have created to
each array element.
xx) Invoke the method computeTax in the class Employee for each Employee object to
compute the value of the attribute tax. Suppose that the value of the parameter taxRate is
0.03.
yy) Update the value of the attribute salary of each Employee object using the method
getNetSalary of the class Employee.
zz) Invoke the method getAverageSalary in the class Employee to compute the average
salary of each Employee object.