NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
JANUARY 2013 EXAMINATION

COURSE CODE:                                                                              CIT383

COURSE TITLE:                                                                             Introduction to Object-Oriented Programming

TIME ALLOWED:                                                                          2½ Hours

INSTRUCTIONS:                                                                            Answer any Four (4) Questions

Q1.a     Give the full meaning of the following acronyms:

(i)        OS                    (ii)       GB                   (iii)      FTP                 (iv)      CRT

(v)       ADT                (vi)      OOD                (vii)     JVM                 (viii)    API

(ix) DLSs                                                                                                                  (1 mark each)

      b.   How would you explain an Object to a layman?                                                                 (4 marks)

      c.    List three Object-Oriented Programming concepts                                                          (4.5 marks)

Q2.a     What do you understand by the term Recursive Methods?                                             (3 marks)

      b.   List and explain two main types of polymorphism. Give an example of each.                (4 marks)

      c.    Enumerate, giving examples, any four (4) examples of Message passing styles            (4 marks)

      d.   Explain the term “downcasting”                                                                                           (8 marks)       

Q3.a     What is the difference between a Class and an Object?                                                   (10 marks)

      b.   What do you understand by the term methods?                                                               (3 marks)

      c.    List five (5) examples of methods                                                                                       (10 marks)

      d.   What is another name for dynamic binding?                                                                     (2 marks)     

Q4.a     What is an Object – Oriented Programming?                                                                      (6 marks)

      b.   Outline and explain two advantages of software reusability                                            (4 marks)

      c.    List two major aspects of Object Oriented Programming that promotes software reuse                        (4 marks)

      d.   Differentiate between an abstract class and a concrete class                                          (6 marks)      

Q5.a     Write a short note on each of the following:

1. Overloaded Method and Overridden Method                                            (5 marks)

(ii)       Local Variables and Instance Variables                                                      (5 marks)

(iii)      Set and Get Methods                                                                                                  (5 marks)

      b.   What do you understand by Recursive Operator                                                                          (4 marks)

      c.    Mention the three (3) ways to call a method                                                                      (6 marks)  

Q6.a     What do you understand by Operator Overloading?                                                        (7 marks)

     b.    List and explain three key restrictions to overloading the conversion operators         (6 marks)

     c.     List the three (3) logical operators that can be directly overloaded for a class                        (6 marks)

     d.    Mention any two programming languages that allow Overloading of an Operator       (6 marks)