Faculty of Information Technology
Department of Software Engineering
Examination Paper
Philadelphia University
Lecturer
: Dr. Ali Fouad
Coordinator
: Dr. Ali Fouad
Internal Examiner : Dr. Samer Hanna
Advanced Object Oriented Programming (721324) Sec. 1
Date: 22-12-2013
Second Exam.
First Semester of 2013-2014
Time: 50 minutes
Information for Candidates
1. This examination paper contains four questions, totaling 22 marks.
2. The marks for parts of questions are shown in round brackets.
Advice to Candidates
1. You should attempt all questions.
2. You should write your answers clearly.
I. Basic concepts
Objective: The aim of the question in this part is to evaluate your knowledge and skills concerning with
the basic concepts of object oriented.
Question1 (4 marks)
What will the following python code display?
class Parent:
# define parent class
parentAttr = 100
def __init__(self):
print "Calling parent constructor"
def parentMethod(self):
print 'Calling parent method'
def setAttr(self, attr):
Parent.parentAttr = attr
def getAttr(self):
print "Parent attribute :", Parent.parentAttr
class Child(Parent): # define child class
def __init__(self):
print "Calling child constructor"
def childMethod(self):
print 'Calling child method'
c = Child()
# instance of child
c.childMethod() # child calls its method
c.parentMethod() # calls parent's method
c.setAttr(200)
# again call parent's method
c.getAttr()
# again call parent's method
Calling child constructor
Calling child method
Calling parent method
Parent attribute : 200
Each
1 mark
Question2 (3 marks)
How can you implement a property for an attribute self._x for a class in python? (3 mark)
@property
def x(self):
return self._x
@x.setter
def x(self, value):
self._x = value
each statement 0.5 mark
II. Familiar Problem Solving
Objective: The aim of the question in this part is to evaluate your ability to solve problems in object
oriented programming, focusing on constructors, assessors, and other methods.
Question3 (10 marks)
The following code defines the start of a class to represent bank accounts:
class BankAccount(object):
def __init__(self, name, number, balance):
self.name = name
self.number = number
self.balance = balance
1) Add instance methods called deposit(), withdraw() which increase and decrease the balance of the
account. Make sure the withdraw() method doesn't allow the account to go into less than zero, and
__str__ method.
def deposit(self, amt):
self.balance += amt
def withdraw(self, amt):
if self.balance – amt > 0:
self.balance -= amt
def __str__(self):
return “\nname is ”+ self.name+
“\nnumber is”+ str(self.number)+
“\nbalance”+ str(self.balance)+
(5 marks)
each line 0.5
2) Create a subclass of BankAccount called StudentAccount. Every StudentAccount should have an
overdraft limit of 1000. Write a constructor for the new class. Override the withdraw() method to make
sure that students can withdraw and doesn't allow the account to go into less 1000.
class StudentAccount
(BankAccount):
def __init__(self, name,
number, balance):
BankAccount.__init__(self, name,
number, balance)
def withdraw(self, amt):
if self.balance – amt > 1000:
self.balance -= amt
each line 0.5
5 marks
III. Unfamiliar Problem Solving
Objective: The aim of the question in this part is to evaluate that student can solve familiar problems
with ease and can make progress toward the solution of unfamiliar problems, and can set out reasoning
and explanation in clear and coherent manner.
Question4 (5 marks)
Create a class named Bank that uses a list to store accounts which includes the following methods:
constructor method
addAccount method to add new account to the bank
totalBalance that return the total momey in the bank
class Bank :
def __init__(self):
self.d = []
def addAccount(self, e):
self.d.append(e)
def totalBalance (self ):
sum=0
for acc in self.d:
sum=sum + acc.balance
return nd
each line 0.5 point