ISC Computer Science 2026

Your Complete Revision Hub

All ISC PYQs organized, interactive tools for every topic, and smart practice to guarantee that 100/100. Exam on 27th March — let's dominate it!

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Quiz Practice

100+ MCQs from PYQs across all 5 chapters

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K-Map Solver

Interactive 2/3/4-variable K-Map with auto simplification

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Logic Gate Sim

Test AND, OR, NOT, NAND, NOR, XOR live

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Truth Table Gen

Type any Boolean expression → auto truth table

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DS Visualizer

Stack, Queue, Tree — animated step-by-step

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Infix→Postfix

Step-by-step conversion with operator stack trace

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Flashcards

Key definitions and formulas for last-minute revision

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Quick Notes

Condensed theory for every ISC topic

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Programs Bank

ISC PYQ programs with full solutions

📋 Syllabus at a Glance

🔵 Section A

Ch 1: Boolean Algebra — Propositional Logic, Theorems, K-Map, Canonical Forms
Ch 2: Computer Hardware — Logic Gates, Combinational Circuits

🟢 Section B

Ch 3: Programming in Java — Fundamentals, Methods, Recursion, Arrays, Strings, File I/O, Exceptions

🟡 Section C

Ch 4: Inheritance, Interfaces, Polymorphism
Ch 5: Data Structures — Stacks, Queues, Trees, Linked Lists

📚 From ISC PYQs

Quiz Practice

Questions sourced directly from ISC board papers. Select a topic and test yourself!

Questions: Topic: Boolean Algebra

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Correct Answers

🃏 Quick Revision

Flashcards

Click a card to flip it. Navigate with arrows. Perfect for last-minute revision!

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📖 Theory

Quick Notes

Click any topic to expand it. All key points for ISC exam.

🔵 Boolean Algebra

Propositional Logic — Key Terms›

Proposition: A declarative statement that is either TRUE or FALSE (not both)
Tautology: A proposition that is ALWAYS true for all truth value combinations
Contradiction: A proposition that is ALWAYS false for all combinations
Contingency: Neither tautology nor contradiction — sometimes true, sometimes false
Converse of P→Q is Q→P
Inverse of P→Q is ~P→~Q
Contrapositive of P→Q is ~Q→~P (logically equivalent to original)

~(P→Q) ≡ P ∧ ~Q | P→Q ≡ ~P ∨ Q

Boolean Algebra Laws (MOST IMPORTANT)›

Identity: A+0=A, A·1=A
Null/Dominance: A+1=1, A·0=0
Idempotent: A+A=A, A·A=A
Complement: A+A'=1, A·A'=0
Involution (Double Complement): (A')'=A — ISC 2021-22
Commutative: A+B=B+A, A·B=B·A
Associative: A+(B+C)=(A+B)+C
Distributive: A(B+C)=AB+AC, A+BC=(A+B)(A+C)
Absorption: A+AB=A, A(A+B)=A
De Morgan's: (A+B)'=A'·B', (A·B)'=A'+B'
Duality Principle: Interchange AND↔OR and 0↔1

K-Map Rules & Groups›

Groups must be powers of 2: 1, 2 (pair), 4 (quad), 8 (octet)
Groups may wrap around edges (map rolling)
Larger groups = simpler expression (fewer literals)
Each 1 must be in at least one group; 0s go to don't-care only
No redundant groups in final expression
SOP: Group 1s → each group gives an AND term → OR all terms
POS: Group 0s → each group gives an OR term → AND all terms
Pair eliminates 1 variable; Quad eliminates 2; Octet eliminates 3

F = Σ(minterms) [SOP] | F = Π(maxterms) [POS]

Minterms, Maxterms & Canonical Forms›

Minterm (m): Product term where function = 1. Written as Σ notation
Maxterm (M): Sum term where function = 0. Written as Π notation
SOP (Sum of Products): OR of AND terms — from minterms
POS (Product of Sums): AND of OR terms — from maxterms
If SOP minterms = {0,1,3}, then POS maxterms = remaining = {2,4,5,6,7}
Cardinal number = minterm number; Canonical form = full standard form

⚡ Computer Hardware

Logic Gates — Truth Tables Summary›

Gate	Symbol	00	01	10	11	Expression
AND	·	0	0	0	1	F=A·B
OR	+	0	1	1	1	F=A+B
NOT	'	Inverts input				F=A'
NAND	↑	1	1	1	0	F=(A·B)'
NOR	↓	1	0	0	0	F=(A+B)'
XOR	⊕	0	1	1	0	F=A⊕B
XNOR	⊙	1	0	0	1	F=(A⊕B)'

NAND and NOR are universal gates — any circuit can be built with only NAND or only NOR
XOR output is 1 when inputs are different (odd number of 1s for multiple inputs)

Combinational Circuits›

Half Adder: Adds 2 bits. Sum=A⊕B, Carry=A·B
Full Adder: Adds 3 bits. Sum=A⊕B⊕C, Carry=AB+BC+AC
Decoder: n inputs → 2ⁿ outputs. Converts binary to individual lines
Encoder: Reverse of decoder. 2ⁿ inputs → n outputs
Multiplexer (MUX): Data selector. 2ⁿ inputs + n select lines → 1 output
4:1 MUX has 4 data inputs, 2 select lines, 1 output
8:1 MUX has 8 data inputs, 3 select lines, 1 output

☕ Java Programming

Java Fundamentals — Key Definitions›

JVM: Java Virtual Machine — abstract machine that runs Java bytecode
JDK: Java Development Kit — superset of JRE, includes compiler (javac)
JIT: Just-In-Time Compiler — speeds up execution by compiling bytecode to native code at runtime
Bytecode: Machine instruction for Java processor chip — platform independent
Wrapper classes: Integer, Double, Character, Boolean — wrap primitives as objects
static: Belongs to class, not instance. Shared by all objects
final: Variable=constant, Method=cannot override, Class=cannot extend

int → Integer | double → Double | char → Character | boolean → Boolean

Recursion — Base Case & Recursive Case›

Base case: The terminating condition — when recursion stops
Recursive case: The function calls itself with a smaller/simpler input
Every recursive function MUST have a base case to avoid infinite recursion
Recursion uses the call stack (LIFO) — each call adds a new stack frame
Tail recursion: Recursive call is the last statement — can be optimized

factorial(n) = n * factorial(n-1) | Base: factorial(0) = 1

fibonacci(n) = fibonacci(n-1) + fibonacci(n-2) | Base: f(0)=0, f(1)=1

Exception Handling›

Exception: Abnormal condition at runtime that disrupts normal program flow
Checked exceptions: Compiler forces you to handle them (IOException, FileNotFoundException)
Unchecked exceptions: Runtime exceptions (ArrayIndexOutOfBounds, NullPointer, InputMismatch)
try — code that might throw; catch — handle it; finally — ALWAYS runs
throw — manually throw an exception object
throws — declare a method may throw an exception
finally block always executes — even after return or exception

🔗 Inheritance & OOP

Inheritance — Complete Summary›

IS-A test: Use extends ONLY when child IS-A parent
Java supports: single, multilevel, hierarchical. NOT multiple (via classes)
super(): Calls parent constructor — must be FIRST statement
super.method(): Calls overridden parent method
protected: Accessible in same package + all subclasses
Method overriding: Same name, same params, same return type in subclass
Dynamic binding: Runtime resolution based on OBJECT type (not reference type)
abstract class: Cannot instantiate. Can have abstract + concrete methods
interface: All methods public+abstract, all fields public+static+final
A class can implement MULTIPLE interfaces

class Dog extends Animal implements Runnable, Serializable { }

🌳 Data Structures

Stack — LIFO›

LIFO: Last In First Out
Push: Add to TOP. Check overflow first (if TOP == MAX-1)
Pop: Remove from TOP. Check underflow first (if TOP == -1)
Peek/Top: View top element without removing
Overflow: Pushing to a full stack
Underflow: Popping from an empty stack (TOP = -1)
Applications: Recursion, expression evaluation, parenthesis matching, undo
Nested method calls implemented using stacks

Push: TOP = TOP+1; arr[TOP] = value

Pop: value = arr[TOP]; TOP = TOP-1

Queue — FIFO›

FIFO: First In First Out
Insertion at REAR; deletion at FRONT
Deque (Double-ended queue): Insertion and deletion at BOTH ends
Input-restricted deque: Insertion at one end, deletion at both ends
Output-restricted deque: Insertion at both ends, deletion at one end
Applications: FCFS scheduling, Round Robin, CPU task queuing, BFS

Enqueue: REAR=REAR+1; arr[REAR]=value

Dequeue: value=arr[FRONT]; FRONT=FRONT+1

Binary Tree — Traversals›

Inorder (LNR): Left → Root → Right → gives sorted order for BST
Preorder (NLR): Root → Left → Right → used to copy tree
Postorder (LRN): Left → Right → Root → used to delete tree
Leaf node: node with no children
Root: topmost node with no parent
Complete binary tree of depth d: 2^(d+1) - 1 total nodes
Leaf nodes in complete binary tree of depth d: 2^d

Inorder example: A B C D E F G for a balanced BST

Linked List›

Each node: data + next pointer
Singly linked: One-way traversal; last node's next = null
Doubly linked: Each node has prev + next pointers
Circular: Last node points back to first
Overflow (linked list): When no memory available for new node
Insertion/deletion is O(1) once position found (no shifting)
Random access is O(n) — must traverse from head

Infix → Postfix Conversion Rules›

Operands go directly to output
( → push to stack
) → pop and output until matching (
Operator: pop operators of equal/higher precedence, then push current
End: pop all remaining operators to output

Precedence: ^ > * / > + -

A*(B+C/D)-E/F → ABCD/+*EF/-

💻 ISC PYQ Programs

Java Programs Bank

Complete ISC-style programs with full solutions. Click to expand.

🗺️ Interactive Tool

K-Map Solver

Click cells to toggle 0/1. The tool auto-identifies groups and gives the simplified expression.

Variables: Mode:

⚡ Interactive

Logic Gate Simulator

Toggle inputs A and B to see real-time gate output. Test all fundamental and universal gates.

Input A

Input B

Input C (XOR-3)

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Universal Gates

NAND and NOR are called universal gates because any Boolean function can be implemented using only NAND gates or only NOR gates. This is frequently asked in ISC exams!

📊 Auto Generator

Truth Table Generator

Enter a Boolean expression and get a complete truth table instantly.

Use: AND, OR, NOT, NAND, NOR, XOR, XNOR | Variables: A, B, C, D (single letters)

🌳 Animated

Data Structure Visualizer

Push, pop, enqueue, dequeue — watch it animate live!

Stack initialized. LIFO — Last In, First Out

🔄 Step-by-Step

Infix → Postfix Converter

Enter an infix expression and see the complete step-by-step conversion with operator stack trace.

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Conversion Rules (memorize these)

1. Operand → output directly 2. ( → push to stack 3. ) → pop until ( 4. Operator → pop higher/equal precedence operators first, then push 5. End → pop all

Your Complete Revision Hub

Interactive Study Guides

📋 Syllabus at a Glance

🔵 Section A

🟢 Section B

🟡 Section C

Quiz Practice

Flashcards

Quick Notes

🔵 Boolean Algebra

⚡ Computer Hardware

☕ Java Programming

🔗 Inheritance & OOP

🌳 Data Structures

Java Programs Bank

K-Map Solver

Logic Gate Simulator

Truth Table Generator

Data Structure Visualizer

Infix → Postfix Converter