ISC 2026 Computer Science Question Paper for Class 12

About this paper

This is ISC Class 12 Computer Science Paper 1 (Theory), code 868A, from the 2026 board examination. It carries 70 marks and three hours, plus fifteen minutes to read the paper. There are 11 questions. Part I, worth 20 marks, is compulsory and mixes multiple-choice items, a prefix conversion and a method that tests a Tech number. Part II, worth 50 marks, has three sections, with any two questions from each. Section A includes a Dragon Warrior truth table, a full adder and a Karnaugh map. Section B is Java: adding two times, a trimorphic number, and rearranging a word by ASCII value. Section C is a browser-history stack, a hotel bill by inheritance, a linked list and a binary tree. This copy has the questions only.

Exam

ISC Class 12

Subject

Computer Science

Year

2026

Paper code

868A

Maximum marks

70

Time allowed

3 hours + 15 min reading

Questions

11

Pages

12

Answers included

No, questions only

Paper pattern

• Part I

  20 marks

  Questions 1 and 2, all compulsory: multiple-choice and assertion–reason items, a prefix conversion and two Java methods

• Section A

  20 marks

  Questions 3–5, ten marks each; answer any two. A decoder, a Dragon Warrior truth table, a full adder and a Karnaugh map

• Section B

  20 marks

  Questions 6–8, ten marks each; answer any two. Java classes for adding two times, a trimorphic number and a pendulum rearrangement of a word

• Section C

  10 marks

  Questions 9–11, five marks each; answer any two. A browser-history stack, a hotel bill by inheritance, a linked list and a binary tree

Topics covered

• Boolean algebra and duality
• Propositional logic
• Karnaugh maps and Gray code
• Decoders and full adders
• Recursion and complexity
• Number systems
• Strings and ASCII
• Inheritance
• Stacks
• Linked lists and binary trees

Questions from this paper

1. A Tech number has an even count of digits, and the square of the sum of its two equal halves equals the number. Show that 2025 is a Tech number because (20 + 25)² = 2025.
2. What does workOut(220) return, and what is the method doing apart from recursion?
3. Class TimeOp adds two times stored as hours, minutes and seconds. 6 hours 35 minutes 40 seconds plus 7 hours 45 minutes 30 seconds is 14 hours 21 minutes 10 seconds.
4. A trimorphic number is one whose cube ends with the number itself. 24³ = 13824, which ends in 24, and 5³ = 125, which ends in 5.
5. Class PendulumS places the lowest-ASCII character of an uppercase word at the centre, the next to its right, the next to its left, and so on. COMPUTER becomes TPMCEORU.
6. Under the laws of the Valley of Peace, a candidate becomes the Dragon Warrior by belonging to the Panda Clan and training for more than five years, or by holding the Secret Chi Power without belonging to that clan, or by a Grand Master's recommendation without the clan or the training. Write the SOP expression for X(C, T, P, R).