Lesson 2.3.1

2.3.1 Defensive design Quiz: OCR Computer Science, Unit 9

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2.3.1, Defensive design: 20 multiple choice questions for the OCR GCSE Computer Science (J277), Unit 9: Producing robust programs, written with Revision Ninja.

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The 20 questions

  1. What defensive design practice involves planning for users entering invalid or unexpected data?

    • Anticipating misuse
    • Input validation
    • Code commenting
    • File handling

  2. Which validation check ensures an input contains a specific number of characters?

    • Presence check
    • Format check
    • Length check
    • Range check

  3. Which security process confirms the identity of a user via a username and password?

    • Iteration
    • Maintainability
    • Validation
    • Authentication

  4. What term describes writing code that is easy to understand, change and fix later?

    • Authentication
    • Casting
    • Maintainability
    • Concatenation

  5. What practice uses clear and consistent identifiers for variables and subprograms?

    • Naming conventions
    • File handling
    • String slicing
    • Input validation

  6. What formatting feature is used in source code to show the structure of loops and selections?

    • Casting
    • Indentation
    • Comments
    • Global scope

  7. What is the main benefit of including comments within source code?

    • Explains code logic
    • Speeds up compilation
    • Enforces data types
    • Reduces file size

  8. Which validation check confirms that a number lies between 1 and 100?

    • Type check
    • Range check
    • Presence check
    • Length check

  9. A program asks for an age but the user types 'twelve'. Which validation check detects this?

    • Length check
    • Presence check
    • Type check
    • Range check

  10. A password must be at least 8 characters long. Which check enforces this?

    • Length check
    • Presence check
    • Type check
    • Range check

  11. A form must not be submitted with an empty name field. Which check is needed?

    • Presence check
    • Type check
    • Length check
    • Range check

  12. Which approach best improves code maintainability when calculating tax repeatedly?

    • Terminal testing
    • Global variables
    • Using sub programs
    • Inline comments

  13. Which practice most helps other programmers understand complex selection statements?

    • Comments and indentation
    • Normal test data
    • Input validation
    • Syntax errors

  14. Which defensive design feature stops users from guessing passwords with infinite attempts?

    • Syntax checking
    • Account lockouts
    • Presence checks
    • Normal data

  15. Which defensive design feature checks the identity of a user?

    • Input validation
    • Error handling
    • Iterative testing
    • Authentication

  16. Which combination of validation checks is best suited for checking a date of birth?

    • Length and lookup
    • Presence and type
    • Range and format
    • Format and presence

  17. Which software development property is improved by using meaningful identifiers and comments?

    • Latency
    • Portability
    • Maintainability
    • Concurrency

  18. Which technique is an example of defensive design anticipating misuse?

    • Input validation
    • Syntax checking
    • Terminal testing
    • Code commenting

  19. What is a key maintainability benefit of using sub programs?

    • Automatic debugging
    • Code reuse
    • Lower memory usage
    • Faster translation

  20. Why are password characters usually hidden with asterisks on screen?

    • Checking data presence
    • Preventing shoulder surfing
    • Validating data types
    • Preventing syntax errors

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