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Paper 2 is the second examination you'll face in IB Computer Science. In this post, we’ll provide a thorough breakdown of IB Computer Science Paper 2, ensuring you are familiarised with the structure of the exam and know what type of questions to expect based on the updated 2027 curriculum.
IB Computer Science Paper 2
At SL, Paper 2 accounts for 35% of the student's final subject grade, while at HL it accounts for 40% of the student's final grade.
SL students have 1 hour 15 minutes, while HL students are given 2 hours to complete Paper 2.
Paper 2 consists of compulsory extended-response questions linked to Theme B: Computational thinking and problem-solving.
One question in the paper will focus specifically on algorithmic thinking without the need to interpret or write code.
There are two versions of the paper – one for students who have studied Python and one for students who have studied Java.
HL students will face additional questions specifically covering HL-only topics, such as abstract data types and advanced OOP.
Typical Paper 2 SL Question
A local library uses a digital system to manage its book loans. The system needs to track student IDs and the dates books are due.
(a) Construct a flowchart to represent an algorithm that checks if a book is overdue and calculates a fine of $0.50 per day. [4]
(b) Describe how a try/except (Python) or try/catch (Java) block could be used to handle a situation where a user enters a non-numeric value for a student ID. [2]
(c) Identify an appropriate data type for storing the "fine amount" and justify your choice. [2]
(d) Explain one advantage of using a dynamic List or ArrayList rather than a static array to store the titles of books currently borrowed by a student. [2]
(e) Construct a code snippet that uses a for loop to traverse an array of book titles and prints only the titles that start with the letter "T". [4]
Typical Paper 2 HL Question
A logistics company is developing a system to manage package deliveries using a custom software architecture.
(a) Evaluate the use of a Binary Search Tree (BST) versus a Linked List for storing and searching for package tracking numbers in a system that requires frequent data retrieval. [4]
(b) Sketch a UML class diagram showing the relationship between a parent class Delivery and a child class ExpressDelivery, including at least two attributes and one method for each. [4]
(c) Explain the role of polymorphism in this system, specifically how a single method call like calculateShipping() could behave differently for different types of delivery objects. [3]
(d) Construct a recursive algorithm in pseudocode to find a specific package ID in a sorted list of IDs. [4]
(e) Describe how a Stack (LIFO) data structure could be used to implement an "undo" feature for the last five delivery entries made by an operator. [2]
How to succeed in Computer Science Paper 2?
To do well in IB Computer Science Paper 2, focus on mastering the practical application of Theme B. It is essential to be proficient in your chosen programming language (Java or Python) and understand how to manipulate data structures like arrays, lists, stacks, and queues. Practice tracing and constructing algorithms, as one question will require algorithmic thinking without code. For HL students, ensure a deep understanding of recursive algorithms and abstract data types. We highly recommend practicing with various problem-solving scenarios to improve your ability to design efficient, modular solutions.
We hope you found this post helpful in learning more about IB Computer Science Paper 2. For more useful materials associated with the IB, check out the wide variety of IA, EE and TOK exemplars available at Clastify and other guides available on our blog.
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