Computer Science 2020 — CSS Past Paper

NOTE: Paper two is published separately.

NOTE: You can download this paper, the links are given at the end of the page.

FEDERAL PUBLIC SERVICE COMMISSION

COMPETITIVE EXAMINATION-2020 FOR RECRUITMENT TO POSTS IN BS-17 UNDER THE FEDERAL GOVERNMENT

COMPUTER SCIENCE, PAPER-I

TIME ALLOWED:

THREE HOURS
PART-I(MCQS): MAXIMUM 30 MINUTES
PART-I (MCQS) MAXIMUM MARKS = 20
PART-II MAXIMUM MARKS = 80

NOTE:

(i) Part-II is to be attempted on the separate Answer Book.
(ii) Attempt ONLY FOUR questions from PART-II, by selecting TWO questions from EACH SECTION. ALL questions carry EQUAL marks.
(iii) All the parts (if any) of each Question must be attempted at one place instead of at different places.
(iv) Write Q. No. in the Answer Book in accordance with Q. No. in the Q.Paper.
(v) No Page/Space be left blank between the answers. All the blank pages of Answer Book must be crossed.
(vi) Extra attempt of any question or any part of the question will not be considered.

PART-II

SECTION-A

Q. No. 2. (a) Write a C/C++ program which implements binary logical ‘AND’, ‘OR’ and ‘NOT’ gates. The program takes binary numbers and desired logical gate as inputs and outputs the desired output of the gate. (b) Write a C/C++ program which inputs a number from a user and prints Fibonacci series up to the number. (c) Explain the concept of abstract class with an example (8) (7) (5) Q. No. 3. (a) Write standard ports for following services HTTP, FTP, SMTP, HTTPS, DNS. (b) Design an appropriate interface for citizen portal mobile application. The interface should contain different features which are part of the portal application. The Interface may contain different screens to support these features. (c) If you are transferring a file over the Internet, would you prefer TCP or UDP as the underlying protocol. Explain (d) If you are transferring live audio in real-time over the Internet, would you prefer TCP or UDP as the underlying protocol. Explain. (4) (8) (4) (4) Q. No. 4. (a) Write a program to perform mathematical operations of addition, subtraction and multiplication on complex numbers. Each operation should be supported by a separate method. (b) How object encapsulation is useful? Explain. (c) Write a program to convert numbers into words. For instance, if the user types 123, the program should give output one hundred and twenty three. The program should continue functioning until the user types quit. (8) (4) (4) Q. No. 5. A university maintains records for students, Faculty, and academic record. Following three classes are part of the system Student (ID, Name, Age, Address, Contact, Program, CGPA) Teachers (ID, Name, Age, Address, Highest Degree, Subjects, Salary) Courses (Semester, Course Code, Student ID, Teacher ID, Grade). All the data is stored in files (a) Draw a class diagram to represent the three classes and their relationships (b) Write C++ programs to compute following: i. Add a student ii. Add a course iii. Find a student with respect to CGPA iv. Add a Teacher v. Update a student (5) (15)

SECTION-B

Q. No. 6. John rides a Van service from new square (S) to the city harbor (T). The van service charges Rs 10 per Km. There are numerous routes between the two points. (a) In order to rip off his customers, John always wanted to use the longest path. To find the longest path, John evaluates all the possible paths and selects the longest path. Write an algorithm to select the longest path using this approach. (b) Compute the complexity of this algorithm and determine that whether it is in P, NP, or NP-complete. (c) Write an algorithm to find a minimum distance between ‘S’ and ‘T’. (d) Derive the complexity of this algorithm. (7) (3) (7) (3) Q. No. 7. (a) How many tokens are there in in this C code : printf(“k = %d, &k = %x”, k, &k); (b) Create State Transition Table from the following graph

Computer Science 2020, Paper one, graph 1

(c) Draw Finite State Automata which accepts following input. i. JIM ii. JMI iii. JJIIM iv. JJMMII (d) Determine which of these inputs are valid for the FSM shown below:

Computer Science 2020, Paper one, graph 2

i. aaaaa ii. ababa iii. abcabc iv. abccba v. acbcd vi. acbcdcd (5) (5) (4) (6) Q. No. 8. (a) Is P = NP? Comment (b) Suppose you are representing a social network (such as facebook) as a graph. Devise an algorithm through which you can determine friends of friends. (c) Explain the complexity of this algorithm (d) Optimal problems are generally NP hard problems. Is it appropriate to use heuristics based approaches? (4) (7) (5) (4)