MCQs on Introduction to Haskell | Haskell

Haskell is a popular functional programming language known for its concise syntax and powerful abstractions. Learning its basics, like syntax, structure, and tools like GHC and Cabal, is essential for efficient programming.

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1. Overview of Functional Programming

1. What is a key characteristic of functional programming?
   a) Mutable state
   b) Use of loops
   c) Immutability of data
   d) Object-oriented principles
2. Which paradigm does Haskell primarily follow?
   a) Procedural
   b) Functional
   c) Object-Oriented
   d) Logic
3. What does “pure function” mean in Haskell?
   a) A function without arguments
   b) A function without side effects
   c) A function with a return value
   d) A function defined inside another
4. In functional programming, functions are treated as:
   a) Variables
   b) First-class citizens
   c) Immutable structures
   d) Objects
5. Which feature of functional programming ensures lazy evaluation in Haskell?
   a) Currying
   b) Referential transparency
   c) Lambda calculus
   d) Lazy loading
6. What is the primary benefit of immutability in functional programming?
   a) Increased performance
   b) Simplified debugging and testing
   c) Reduced code length
   d) Automatic garbage collection
7. Functional programming emphasizes:
   a) Statements and control flow
   b) Objects and inheritance
   c) Expressions and declarations
   d) Procedural steps
8. Which concept is NOT commonly associated with functional programming?
   a) Higher-order functions
   b) Recursion
   c) Classes and inheritance
   d) Pure functions
9. In Haskell, functions that return new values without altering inputs are called:
   a) Impure functions
   b) Recursive functions
   c) Pure functions
   d) Lazy functions
10. What mathematical foundation is functional programming based on?
    a) Lambda calculus
    b) Boolean algebra
    c) Set theory
    d) Graph theory

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2. Installing Haskell (GHC, Stack, Cabal)

11. What is GHC in Haskell?
    a) A library for Haskell programs
    b) Haskell’s runtime environment
    c) Haskell’s compiler
    d) Haskell’s debugger
12. Which tool is used for dependency management in Haskell?
    a) GHC
    b) Cabal
    c) Stack
    d) Both b and c
13. What command installs Haskell using Stack?
    a) stack setup
    b) ghc install
    c) cabal init
    d) haskell setup
14. What is the purpose of Cabal in Haskell?
    a) Code debugging
    b) Creating and managing Haskell packages
    c) Running Haskell code
    d) Formatting Haskell programs
15. Which command is used to compile a Haskell program with GHC?
    a) ghc build
    b) ghc compile
    c) ghc filename.hs
    d) stack build
16. What is the main difference between Cabal and Stack?
    a) Cabal is newer, while Stack is older
    b) Stack provides version isolation, while Cabal doesn’t
    c) Cabal manages libraries, while Stack doesn’t
    d) Stack is faster than Cabal
17. How do you verify the installed version of GHC?
    a) ghc -v
    b) ghc --version
    c) ghc info
    d) ghc setup
18. Which command initializes a new Haskell project using Stack?
    a) stack init
    b) stack new project-name
    c) stack create project
    d) stack start
19. What does stack ghci do?
    a) Opens a REPL environment
    b) Compiles the Haskell project
    c) Installs Haskell dependencies
    d) Runs a Haskell script
20. Which tool automatically resolves library dependencies in Haskell?
    a) GHC
    b) Stack
    c) Cabal
    d) Both b and c

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3. Writing and Running Basic Haskell Programs

21. What is the file extension for Haskell source files?
    a) .hs
    b) .hsk
    c) .hl
    d) .haskell
22. How do you print “Hello, World!” in Haskell?
    a) println "Hello, World!"
    b) echo "Hello, World!"
    c) print "Hello, World!"
    d) putStrLn "Hello, World!"
23. What does the main function represent in Haskell?
    a) Entry point of the program
    b) A helper function
    c) A reserved keyword
    d) A library function
24. Which of the following runs a Haskell script directly?
    a) runhaskell filename.hs
    b) haskell filename.hs
    c) ghci filename.hs
    d) compile filename.hs
25. What happens when you execute ghci without arguments?
    a) Compiles the program
    b) Opens an interactive REPL
    c) Exits with an error
    d) Installs missing packages
26. How do you declare a function in Haskell?
    a) function name args = expression
    b) def name args: expression
    c) name args = expression
    d) func name args = expression
27. What is a module in Haskell?
    a) A precompiled library
    b) A namespace for grouping related functions
    c) A set of data types
    d) A compiler directive
28. How do you import a module in Haskell?
    a) import module-name
    b) include module-name
    c) load module-name
    d) require module-name
29. What is the result of print (2 + 3) in Haskell?
    a) 2 + 3
    b) 5
    c) An error message
    d) Nothing
30. Which function is used to read input in Haskell?
    a) input
    b) getLine
    c) readLn
    d) readInput

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Answer Key

Qno	Answer
1	c) Immutability of data
2	b) Functional
3	b) A function without side effects
4	b) First-class citizens
5	d) Lazy loading
6	b) Simplified debugging and testing
7	c) Expressions and declarations
8	c) Classes and inheritance
9	c) Pure functions
10	a) Lambda calculus
11	c) Haskell’s compiler
12	d) Both b and c
13	a) stack setup
14	b) Creating and managing Haskell packages
15	c) ghc filename.hs
16	b) Stack provides version isolation, while Cabal doesn’t
17	b) ghc --version
18	b) stack new project-name
19	a) Opens a REPL environment
20	d) Both b and c
21	a) .hs
22	d) putStrLn "Hello, World!"
23	a) Entry point of the program
24	a) runhaskell filename.hs
25	b) Opens an interactive REPL
26	c) name args = expression
27	b) A namespace for grouping related functions
28	a) import module-name
29	b) 5
30	b) getLine