What the board asks

We went through the ISC board papers, question by question, and matched each question to a topic. Here is what was asked, how often, and what was never asked.

Computer Science: 180 topics in the 2027 syllabus, across 10 units. The board has asked 117 of them at least once. 63 were never asked in the papers we checked.

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CS9 Data Structures

All the topics in Computer Science: Data Structures

Asked topics first, the most asked at the top. Tap a topic to see what to write, the result, the years, and the real board questions.

25 topics shown

#	Topic	Type	Marks	Times asked	Last asked	Status
1	Pre-order, in-order and post-order traversalWrite the order of nodes for the traversal asked, of the whole tree or of the named subtree, applying the rule recursively at every node.	Dry run / output	1	9 papers	2026	Asked
2	Read a tree: leaves, internal nodes, parent, siblings, degreeFrom a drawn binary tree (or its left or right subtree) list the external nodes, internal nodes, siblings or parent of named nodes, and state the degree of named nodes.	Diagram	1	8 papers	2025 improvement	Asked
3	Traverse a linked list to count, sum, search or displayWrite the algorithm or Java method that starts a temporary pointer at the given first node, handles the empty list, visits every node until null applying the stated test (odd, even, consonant, lower case, age, matching value), updates a count, sum or product, and returns or prints the result as the declaration says.	Program	2	7 papers	2026	Asked
4	Read a tree: level, height, depth and sizeFrom a drawn binary tree state the level or depth of named nodes, the height or depth of the whole tree, and the size of the tree or of a subtree, using the convention the question gives (root at level 0).	Diagram	1	7 papers	2026	Asked
5	Convert an infix expression to postfixConvert by fully bracketing in order of precedence and moving each operator after its operands, or by the stack method in a table, showing the steps and giving the final postfix expression.	Sum	2	6 papers	2025 improvement	Asked
6	Stack: name the entity and state its principleIdentify from a description that the structure is a stack, state the LIFO principle, name push, pop, overflow and underflow, and give one application.	Statement	1	3 papers	2026	Asked
7	Write the push and pop methods of a stack classWrite the add method that checks top == cap - 1 for overflow (print the given message) else does top++ and stores, and the remove method that checks top == -1 for underflow (return the given value) else returns the element and decrements top.	Program	4	3 papers	2026	Asked
8	Convert an infix expression to prefixConvert by fully bracketing in order of precedence and moving each operator before its operands, showing the steps and giving the final prefix expression.	Sum	2	3 papers	2026	Asked
9	Write the insert and delete methods of a circular queueWrite the insert method that tests the full condition with modulo arithmetic and prints the given message else stores and advances rear by (rear + 1) % cap, and the delete method that tests for empty and returns the given value else returns the front element and advances front by (front + 1) % cap.	Program	4	3 papers	2025 improvement	Asked
10	Queue: name the entity and state its principleIdentify from a description that the structure is a queue, state the FIFO principle, and name the rear (insertion) and front (deletion) ends with one application.	Statement	1	2 papers	2025 improvement	Asked
11	Linear queue versus circular queue; applicationsState how a circular queue reuses freed cells (rear wraps to the front) while a linear queue cannot, and give one application of a circular queue.	Comparison	1	2 papers	2025	Asked
12	Insert and delete methods of a linear queue classWrite the insert method that checks for a full queue (rear at capacity) and prints the given message else stores at rear and moves rear, and the delete method that checks for an empty queue (front == rear) and returns the given value else returns the front element and moves front, resetting both pointers when the queue empties.	Program	4	2 papers	2019	Asked
13	Add and remove methods at either end of a dequeueWrite the methods asked from addFront, addRear, popFront and popRear, each with its own overflow or underflow test and the given message or return value, moving front and rear in the correct direction.	Program	4	1 paper	2023	Asked
14	Stack versus queue (and dequeue)Give matched points of difference: principle (LIFO and FIFO), number of open ends, names of operations, and an example use of each; say how a dequeue can behave as either.	Comparison	1	1 paper	2023	Asked
15	Linked list node: data part, reference part, start, nullDescribe a node of a single linked list (data field and reference to the next node), the role of the start pointer and of null at the end, and say why the reference part matters.	Statement	1	1 paper	2023	Asked
16	Insert a node at the beginning, end or a positionWrite the algorithm or method that creates the new node, handles an empty list, and links it at the front, after the last node (walking until next == null) or after a given node, without losing the rest of the list.	Program	2	1 paper	2023	Asked
17	Binary tree versus single linked listGive matched points of difference: linear versus hierarchical, one reference per node versus two (left and right), and traversal in one order versus several.	Comparison	2	1 paper	2020	Asked
18	Binary tree terms: root, internal and external nodes, degreeDefine a binary tree and the terms root, parent, child, siblings, internal node, external node (leaf), subtree and degree of a node, and state the difference between internal and external nodes.	Statement	2	1 paper	2019	Asked
19	State of a stack or queue after given operationsDraw the array after each push, pop, insert or delete in a given sequence, mark top or front and rear at each step, and write the value returned or the overflow or underflow message.	Dry run / output	2	never		Never asked
20	Define a data structure as an interface and implement itWrite an interface listing the operations (for example push, pop, isEmpty) and a class that implements it with an array, giving every method public; know that a second class can implement the same interface differently.	Program	4	never		Never asked
21	Delete a node from a linked listWrite the algorithm or method that deletes the first node, the last node or the node holding a given value, keeping a pointer to the previous node and handling the empty list and the one-node list.	Program	2	never		Never asked
22	Reverse a single linked listWrite the algorithm or method that reverses the links in place with three pointers (previous, current, next) and returns or sets the new start.	Program	2	never		Never asked
23	Extract an element or a sublist from a linked listWrite the algorithm or method that returns the element at a given position, or builds a new list from the nodes between two positions (or those meeting a condition), handling positions beyond the list.	Program	2	never		Never asked
24	Complete and balanced binary treesDefine a complete binary tree and a balanced binary tree and decide, with a reason, whether a drawn tree is complete or balanced.	Give reason	1	never		Never asked
25	Evaluate a postfix expression using a stackScan the postfix expression left to right, push operands, pop two on each operator, apply it in the right order and push the result, showing the stack after each symbol and the final value.	Dry run / output	2	never		Not in syllabus

This list was made from the 2027 syllabus and checked with 9 board papers, including the 2027 specimen paper. It is not yet checked with the textbook.

The 10 topics Computer Science papers ask most

Counted on the board papers from 2018 to the 2027 specimen paper, which every unit has been checked against.

1.Principle of duality: state it and write the dualCS1 Boolean Algebra · asked 8 times since 2018
2.Complement of an expression using De Morgan's theoremCS1 Boolean Algebra · asked 8 times since 2018
3.Word problem to truth table and SOP or POSCS1 Boolean Algebra · asked 8 times since 2018
4.K-map reduction of a four-variable POS expressionCS1 Boolean Algebra · asked 8 times since 2018
5.Pre-order, in-order and post-order traversalCS9 Data Structures · asked 8 times since 2018
6.K-map reduction of a four-variable SOP expressionCS1 Boolean Algebra · asked 7 times since 2018
7.Read a tree: leaves, internal nodes, parent, siblings, degreeCS9 Data Structures · asked 7 times since 2018
8.Truth table to classify tautology, contradiction or contingencyCS1 Boolean Algebra · asked 6 times since 2018
9.Convert between cardinal and canonical formsCS1 Boolean Algebra · asked 6 times since 2018
10.Address of an element, row major and column majorCS6 Arrays and Strings · asked 6 times since 2018

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