Swift Programming Best Practices Quiz

1. What is the purpose of using SwiftLint in Swift development?

• To improve runtime performance.
• To manage memory usage.
• To debug network issues.
• To enforce a consistent code style.

2. Which Swift type is preferred for better performance and safety?

• Array types (NSArray, NSMutableArray).
• Value types (structs and enums).
• Reference types (classes).
• Dynamic types (Any, AnyObject).

3. How do you safely unwrap optionals in Swift?

• Using optional types directly.
• Using global variables.
• Using guard statements.
• Using print statements.

4. What is type inference in Swift?

• Type inference automatically converts types at runtime.
• Type inference means variables can only be of one predefined type.
• Type inference requires explicit type declaration from the programmer.
• Type inference is a feature of Swift that allows the compiler to automatically determine the type of a variable or expression based on its context.

5. How do you write a single-line comment in Swift?

• Using a double dash (–).
• Using a pound sign (#).
• Using a semicolon (;).
• Using two forward slashes (//).

6. How do you write a multi-line comment in Swift?

• Enclosing the text between /* and */.
• Placing comments within < > brackets.
• Using the # symbol at the beginning.
• Wrapping comments in //.

7. What is the difference between let and var in Swift?

• Let is used for immutable variables, while var is used for mutable variables.
• Let can only be used within functions, var can be used globally.
• Let and var are interchangeable without restrictions.
• Let is used for optional types, while var is for non-optional types.

8. How do you handle division by zero in Swift?

• By ensuring at least one of the numbers is a floating-point number or by using a try-catch block to handle the error.
• By using a conditional statement to skip the calculation.
• By returning a default value of zero.
• By ignoring the division and moving to the next line of code.

9. What is a tuple in Swift?

• A tuple is a single value that cannot be changed.
• A tuple is a complex class used for object-oriented programming.
• A tuple is an array that can only contain strings.
• A tuple is a lightweight data structure that groups multiple values into a single compound value.

10. How do you check if two strings are equal in Swift?

• Using the `==` operator.
• Using the `===` operator.
• Using the `equals()` function.
• Using the `!= operator.

11. What are the fundamental data types available in Swift?

• Int, Double, String, Array, Dictionary, Set, etc.
• Float, Char, List, Map, Tuple.
• String, Object, Matrix, Queue.
• Boolean, Struct, Label, Hash.

12. How does Swift handle memory management?

• Swift employs garbage collection for memory management.
• Swift does not manage memory automatically at all.
• Swift uses Automatic Reference Counting (ARC) to handle memory management.
• Swift manages memory using manual reference counting.

13. What is the purpose of the `switch` statement in Swift?

• The `switch` statement is used for pattern matching and must be exhaustive.
• The `switch` statement defines a function and returns a value.
• The `switch` statement is used only for numerical comparisons.
• The `switch` statement is a way to declare variables in Swift.

14. How do you create a dictionary in Swift?

• Writing the dictionary on separate lines without any colons or brackets.
• Using square brackets only without any key and value pairs.
• By creating instances of key/value pairs without any formatting or structure.
• Using dictionary literals with a colon : separating each key from its value, and each key-value pair separated by a comma. The entire dictionary is wrapped in square brackets [] (e.g., [key: value]).

15. What is the purpose of the `for-in` loop in Swift?

• The `for-in` loop iterates over a sequence and performs a set of statements for each element.
• The `for-in` loop creates an array of values and returns it.
• The `for-in` loop repeats a code block a fixed number of times.
• The `for-in` loop is used to define a new data type in Swift.

16. How do you avoid force unwrapping optionals in Swift?

• Using only force unwrapping directly.
• Using guard let, if let, guard let as?, if let as?, and optional chaining.
• Using unsafe pointers instead of optionals.
• Using global variables for state management.

17. What is the difference between forced-try expression and try-catch block in Swift?

• Forced-try expression (try!) ignores all errors silently, while a try-catch block does not.
• Forced-try expression (try!) requires additional error handling, while try-catch always succeeds.
• Forced-try expression (try!) can only be used with throws, while try-catch handles non-throwing functions.
• Forced-try expression (try!) will crash with an error message, while try-catch handles errors gracefully.

18. How do you declare properties of an object or struct that shouldn`t change over its lifetime in Swift?

• Using immutable only once.
• Using static instead of dynamic.
• Using let instead of var.
• Using final instead of constant.

19. What is the purpose of access control in Swift?

• Access control encapsulates internal object state.
• Access control eliminates the need for optionals.
• Access control improves memory management efficiency.
• Access control optimizes runtime performance.

20. How do you organize your Swift files?

• Files should be named randomly without structure.
• All files should be stored in a single directory.
• Each type (class, struct, enum) should have its own file.
• Just group files by date modified.

21. What is the Rule of Threes in structuring Swift projects?

• The Rule of Threes states to always use three types of variables in your code.
• The Rule of Threes means you should only write three functions per file.
• The Rule of Threes suggests that every time you end up with three parts of a type, folder, or file that could be grouped together, you should try to do so.
• The Rule of Threes applies only when using third-party libraries in Swift projects.

22. How do you maintain a solid project structure in Swift?

• By randomly organizing files without a clear strategy.
• By using only one file for all classes and functions.
• By copying and pasting code across different files.
• By defining key principles and continuously rearranging things according to those principles.

23. What is the Scout rule in maintaining project structure?

• The Scout rule states that all code must be written in one file to maintain simplicity.
• The Scout rule states that code should be optimized for performance before readability.
• The Scout rule states that whenever you touch a part of the code base, you should try to leave it better than how you found it.
• The Scout rule states that every developer should only work on their own specific section of the codebase without collaboration.

24. How do you handle delegate protocols in Swift?

• Delegate protocols can only have one method defined.
• Delegate protocols should always be declared as public.
• Delegate protocols should be declared with the @objc attribute if they have optional methods.
• Delegate protocols must be implemented in a separate file from the class.

25. What is the purpose of using Markdown for documentation comments in Swift?

• Markdown is used to format the code without any documentation.
• Markdown is only used for styling user interfaces in Swift.
• Markdown serves as a compiler directive in Swift.
• Markdown provides a clear and readable format for documentation comments.

26. How do you write a documentation comment for every declaration in Swift?

• Include only the data type without any descriptive text.
• Write an essay explaining the history of the programming entity.
• Start with a bullet point to outline the features of the declaration.
• Begin with a summary that describes the entity being declared, and use Swift’s dialect of Markdown for documentation.

27. What are the benefits of using Swift types over NS* types from Objective-C?

• Swift types are more concise and expressive, and they avoid the overhead of Objective-C’s dynamic typing.
• Swift types are less efficient and more verbose than NS types.
• Swift types require more extensive boilerplate code than NS types.
• Swift types cannot be used in networking, unlike NS types.

28. How do you handle JSON serialization and deserialization in Swift?

• Rely on NSJSONSerialization for all JSON tasks.
• Only use dictionaries to handle JSON data.
• Use manual encoding and decoding with Codable structs.
• Use the Codable protocol to easily serialize and deserialize JSON data.

29. What is the purpose of using higher-order functions in Swift?

• To automate memory management in Swift.
• To make the code more expressive and functional.
• To reduce the size of the codebase.
• To enforce strict type checking in functions.

30. How do you leverage Swift’s powerful enums?

• Enums in Swift cannot have associated values or methods.
• Enums in Swift support associated values and methods, making them powerful for modeling state and behavior.
• Enums in Swift can only hold integer values and nothing else.
• Enums in Swift only represent simple cases without additional functionality.