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IT Jobs Computer Science MCQs with Answers

179 practice MCQs on Computer Science for IT Jobs tests. Think of your answer first, then open "Show answer and explanation". These are practice questions, not official examination papers.

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Q101. What is the worst-case time complexity of bubble sort?

  1. O(n log n)
  2. O(log n)
  3. O(n^2)
  4. O(n)
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Correct answer: C. O(n^2)

Bubble sort compares adjacent pairs repeatedly.

Q102. Who developed the C programming language?

  1. Bjarne Stroustrup
  2. Dennis Ritchie
  3. James Gosling
  4. Guido van Rossum
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Correct answer: B. Dennis Ritchie

Ritchie created C at Bell Labs.

Q103. Which extension is used for compressed archives?

  1. .mp3
  2. .zip
  3. .docx
  4. .png
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Correct answer: B. .zip

.zip compresses files.

Q104. What is the unique hardware address of a network interface called?

  1. URL
  2. MAC address
  3. DNS
  4. IP address
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Correct answer: B. MAC address

MAC addresses identify NICs.

Q105. What does the 'main()' function represent in C?

  1. A comment
  2. The entry point of the program
  3. A header file
  4. A variable
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Correct answer: B. The entry point of the program

Execution starts at main().

Q106. What does URL stand for?

  1. Universal Resource Link
  2. Uniform Resource Locator
  3. Uniform Reference Locator
  4. Universal Resource Locator
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Correct answer: B. Uniform Resource Locator

A URL is a web address.

Q107. Which command is used to remove files in Linux?

  1. del
  2. remove
  3. erase
  4. rm
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Correct answer: D. rm

rm deletes files.

Q108. Which SQL command removes rows?

  1. DROP
  2. REMOVE
  3. CLEAR
  4. DELETE
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Correct answer: D. DELETE

DELETE removes rows from a table.

Q109. What is the time complexity of linear search?

  1. O(log n)
  2. O(1)
  3. O(n)
  4. O(n log n)
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Correct answer: C. O(n)

Linear search checks each element.

Q110. In an email, what does CC stand for?

  1. Carbon Copy
  2. Common Copy
  3. Courtesy Content
  4. Computer Copy
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Correct answer: A. Carbon Copy

CC sends a copy to others.

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