Computer Science Previous Year Questions (page 12)

Explanation

fstreambase provides operations common to file streams, ifstream gives input, ofstream gives output, and fstream supports simultaneous input and output.

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Errors such as out-of-range index come from the program's own execution, so they are synchronous. Events beyond the program's control, such as keyboard interrupts, are asynchronous.

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p points to a and q points to p, so **q = 3 and *p = 3. b = 2 × (3 + 3) = 12.

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z = x++ + 17 = 33 + 17 = 50 and x becomes 34. y = ++z − ++x = 51 − 35 = 16. So x = 35, y = 16, z = 51.

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Both statements are true: a virtual function must be a member of a class, and it is accessed through object pointers (base-class pointers) for run-time polymorphism. So neither is incorrect.

Explanation

A JOIN combines rows from two or more tables based on a related (common) column between them.

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INSERT is a DML command (and is used as INSERT INTO, not "insert table"). CREATE, ALTER and DROP TABLE are DDL commands.

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Π is projection (choose columns), × is Cartesian product, and σ is selection (choose rows).

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Selecting tuples (rows) that satisfy a condition uses σ: σ Marks>80 (STUDENT). Π selects columns, not rows.

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Denormalization deliberately adds redundancy (merging tables or duplicating data) to cut joins and improve read performance.

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FLOAT stores numbers with decimal points, but BIGINT occupies 8 bytes, not 16. So only I is correct.

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DELETE is a DML command because it manipulates data. ALTER TABLE is DDL, and copy/paste are not SQL statements.

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Cardinality is the number of tuples (50), and degree is the number of attributes (20).

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Both statements are reversed: COUNT(*) counts all rows of the result, while COUNT(column) counts the non-NULL values in a column. So neither is correct.

Explanation

Ctrl+R right-aligns, Ctrl+L left-aligns, Ctrl+E centres and Ctrl+J justifies a paragraph.

Explanation

An Excel file is a workbook, which contains one or more worksheets.

Explanation

Ctrl + Enter inserts a manual page break in Word.

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PowerPoint lets you add pictures, charts, sound effects and tables to slides, so all three are correct.

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Ctrl + ] increases the selected text's font size by 1 point, and Ctrl + [ decreases it by 1 point.

Explanation

Ctrl + G (or F5) opens the Go To dialog in Excel, used to jump to a cell or range.

Explanation

Changes made to the Slide Master (such as a background image) apply to every slide that uses it.

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A website is a collection of related web pages under one domain.

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A user-friendly website should load fast, be accessible and look consistent across browsers. A cluttered design hurts usability.

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A static website serves fixed content that is the same on every load. Content changing at runtime is a feature of dynamic websites.

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<title> must be placed inside <head>, not outside it. It sets the page title shown in the browser tab, and search engines use it.

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The tag described here seems to be <meta> (the tag name is missing in the source). It holds information about the page, such as description, keywords and author.

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HTML puts no limit on the number of <form> elements a page can have (they just cannot be nested).

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An image map is one image with clickable regions (<map>/<area>), where each region links to a different URL.

Explanation

WAV is an audio file format. GIF, JPG and PNG are image formats.

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A frame buffer with one bit per pixel is a bitmap, and one with multiple bits per pixel (for colour or grey levels) is a pixmap.

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Aspect ratio is width : height = 3 : 2. With a height of 4 inches, width = 4 × 3/2 = 6 inches.

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Resolution = pixels ÷ inches = 512 / 2 = 256 pixels per inch.

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The frame buffer (refresh buffer) is the memory that stores the intensity/colour value of every pixel of the screen image.

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Aspect ratio is width to height, e.g., 16 : 9.

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Common topologies are bus, star, ring, mesh, tree and hybrid. "Singleton network" is not a topology.

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The session layer establishes, maintains and terminates sessions. Setting up the logical path (routing) between source and destination is the network layer's job, not the data link layer's.

Explanation

Half duplex is two-way but only one direction at a time, not "multidirectional". Full duplex is bidirectional at the same time. So only II is true.

Explanation

Circuit switching sets up a dedicated path before transfer, and packet switching breaks the data into packets that are routed independently. Both are true.

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Each of the n nodes connects to the other n − 1. Each edge is then counted twice, so there are n(n − 1)/2 edges.

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Quicksort partitions the array around a pivot and recursively sorts the two parts, which is divide and conquer.

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In a B-tree all leaves are at the same level, so statement (C) is false. The others are standard B-tree properties.

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By the handshaking lemma the sum of degrees is 2|E|, which is even, so the number of odd-degree vertices must be even.

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Shortest path is solvable in polynomial time (e.g., Dijkstra), so it is in P. Clique, Hamiltonian cycle and TSP (decision version) are NP-complete.

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In a red-black tree every node is red or black, and a red node's children must be black. Leaves (NIL nodes) are black, not red, so II is false.

Explanation

Add 20 at position 9 as the child of 6, then swap it with 6. Its parent is now 17, so swap again. The parent 23 is larger, so it stops: 23, 20, 14, 17, 13, 10, 1, 5, 6.

Explanation

Kruskal: take Q–R (5), S–T (10), Q–T (15); skip Q–S (20) and R–T (25), which would form cycles; take P–Q (30). Weight = 5 + 10 + 15 + 30 = 60.

Explanation

LISP stands for LISt Processing. Lists are its basic data structure.

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FOPL is First Order Predicate Logic, which uses predicates, variables and quantifiers (∀, ∃) to represent knowledge.

Explanation

In expert systems, the intelligent (knowledge-acquisition) editor is the interface the domain expert or knowledge engineer uses to enter and refine the knowledge base.