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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CS6 Arrays and Strings
All the topics in Computer Science: Arrays and Strings
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.
21 topics shown
| # | Topic | Type | Marks | Times asked | Last asked | Status |
|---|---|---|---|---|---|---|
| 1 | Address of an element, row major and column majorWrite the formula for the stated order, substitute base address, element size, the lower bounds and the number of columns (row major) or rows (column major), and give the final address with working. | Sum | 2 | 7 papers | 2025 improvement | Asked |
| 2 | Design a class rearranging or sorting letters of a wordWrite the class with the word and result members, constructor, input method, the method that builds the new word (swap first and last, sort letters, vowels first, flip halves, pendulum order) by the stated rule, display() and main(). | Program | 10 | 4 papers | 2026 | Asked |
| 3 | Design a two-matrix class with object argumentsWrite the class with the matrix and order members, the parameterised constructor, input and print methods, the method that takes two (or one) objects and compares, adds or transforms their matrices element by element into the current object or a return value, and main() that creates the objects and calls the methods. | Program | 10 | 3 papers | 2025 | Asked |
| 4 | Design a class on letter frequency, tests or codesWrite the class with the word members, constructor, input method, the methods that count or test characters (vowels and consonants, repeated letters, ASCII codes, lowest and highest code, or a letter-shift code) as specified, display() and main(). | Program | 10 | 3 papers | 2025 | Asked |
| 5 | Find base address, order or bound from a given addressWrite the row major or column major formula, put in the known address and element, solve for the unknown (base address, number of rows or columns, or order of a square matrix), and state it. | Sum | 2 | 2 papers | 2026 | Asked |
| 6 | Maximum, minimum, sum and average of array elementsWrite a method that runs one loop over the array (or a word's characters), keeps the running maximum, minimum, position, sum or count as asked, and returns or prints the result in the stated type. | Program | 3 | 2 papers | 2026 | Asked |
| 7 | Fill the blanks in a String-processing methodWrite the exact expression or statement for each marked blank (?1?, ?2?, ...) so that the given method using String methods works, one answer per blank. | Program | 3 | 2 papers | 2026 | Asked |
| 8 | Design a class that tests each word of a sentenceWrite the class with the sentence member, constructor, input method, helper methods that test one word (capital first letter, palindrome, prime length, etc.), display() that splits the sentence into words, applies the tests and prints the words or the count, and main(). | Program | 10 | 2 papers | 2025 improvement | Asked |
| 9 | Design a class joining or reversing arrays of two objectsWrite the class with the array and size members, the constructor, accept(), the method that builds a new object whose array combines the arrays of the two parameter objects in the stated order (reversed, merged, alternate), returns or stores it, display(), and main(). | Program | 10 | 1 paper | 2025 improvement | Asked |
| 10 | Design a class on matrix rows, columns, diagonals or boundaryWrite the class with the matrix and its order as members, the constructor, input and display in matrix form, and the method that works on rows, columns, the two diagonals, the boundary or the sorted elements as asked, and main(). | Program | 10 | 1 paper | 2025 | Asked |
| 11 | Design a class sorting an array by bubble, selection, insertionWrite the class with the array and size data members, the constructor, the input method, the sort method using exactly the named technique and order (ascending or descending), any extra method asked (such as an average), display() and main() that creates the object and calls the methods. | Program | 10 | 1 paper | 2024 | Asked |
| 12 | Design a class to transpose, rotate or mirror a matrixWrite the class with the matrix and size members, the constructor, fillarray(), the method that builds the transposed (or rotated or mirrored) matrix, display() that shows original and result as specified, and main(). | Program | 10 | 1 paper | 2023 | Asked |
| 13 | Design a class sorting or reordering words of a sentenceWrite the class with the sentence and word-count members, constructor, input method, the method that splits the sentence into a String array, sorts or reorders the words (alphabetical, by length, reversed order) and joins them into the result, display() and main(). | Program | 10 | 1 paper | 2023 | Asked |
| 14 | Design a class that merges two words passed as objectsWrite the class with the word and length members, constructor, input method, the method that takes two objects and builds the combined word (alternate characters, then the rest of the longer word) into the current object, display() and main(). | Program | 10 | 1 paper | 2020 | Asked |
| 15 | Array terms: declare, create, index, length, constant-time accessWrite correct definitions and one-line Java examples for declaring and creating single and two-dimensional arrays, the index range, arr.length and arr[0].length, default values, and why access to any element takes constant time. | Statement | 2 | never | Never asked | |
| 16 | Linear search and binary search in an arrayWrite a method that returns the index (or -1) of a key: a linear search over any array, and an iterative binary search on a sorted array using low, high and mid. | Program | 5 | never | Never asked | |
| 17 | Array after each pass of bubble, selection, insertion sortWrite the array after each pass (or after the asked pass) of the named sort on the given data, in the order asked. | Dry run / output | 2 | never | Never asked | |
| 18 | Solve a system of linear equations with a matrixWrite a method that stores the coefficients and constants in a two-dimensional array, eliminates unknowns row by row (Gaussian elimination) and back-substitutes to print each unknown. | Program | 10 | never | Never asked | |
| 19 | Output of String method callsWrite the exact value returned or printed for each call such as length(), charAt(), indexOf(), lastIndexOf(), substring(), concat(), replace(), compareTo(), equals(), toUpperCase(), trim(), including quotes where the answer is a String. | Dry run / output | 2 | never | Never asked | |
| 20 | String versus StringBufferState two or three differences (immutable versus mutable, methods available, efficiency when a string is changed many times) and say when StringBuffer is the better choice. | Comparison | 2 | never | Never asked | |
| 21 | Use StringBuffer methods to build or edit a stringWrite the method body that uses a StringBuffer (append, insert, reverse, setCharAt, deleteCharAt, toString) to build or change the word as asked, and returns or prints the String result; also give the output of given StringBuffer calls. | Program | 3 | never | Never asked |
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