Quiz

Question 1: Variable Declarations

Consider the following Scala code snippet:

val x: Int = 10
var y: Int = 20
y = x + 10
val z: Int = y + 10

What is the value of z at the end of this execution?

A) 20
B) 30
C) 40
D) 50

Question 2: Function Definition

Review the Scala function below:

def multiply(a: Int, b: Int): Int = a * b

What does this function do?

A) Adds two numbers
B) Subtracts two numbers
C) Multiplies two numbers
D) Divides two numbers

Question 3: Immutable List Operations

Given the Scala code:

val numbers = List(1, 2, 3, 4, 5)
val doubled = numbers.map(_ * 2)

What does the doubled list contain?

A) List(2, 4, 6, 8, 10)
B) List(1, 2, 3, 4, 5)
C) List(0, 2, 4, 6, 8)
D) List(3, 4, 5, 6, 7)

Question 4: Pattern Matching

Consider this Scala code snippet using pattern matching:

val greeting = "Hello"

greeting match {
  case "Hello" => "World"
  case "Goodbye" => "Everyone"
  case _ => "Unknown"
}

What is the result of the pattern matching?

A) World
B) Everyone
C) Unknown
D) Error

Question 5: Variable Mutability

Which keyword is used to declare a mutable variable in Scala?

A) let
B) var
C) val
D) const

Question 6: Scala's Type Inference

What does Scala's type inference feature allow you to do?

A) Automatically detect errors in your code
B) Infer the type of variables at runtime
C) Omit the type of a variable when it is declared
D) Change the type of a variable after it is initialized

Question 7: Function Declarations

How do you declare a function in Scala that takes two integers and returns their sum?

A) def sum(x: Int, y: Int): Int = { return x + y }
B) function sum(x: Int, y: Int): Int = x + y
C) def sum(x: Int, y: Int) => x + y
D) Both A and C are correct

Question 8: Using a while Loop

Consider the following Scala code snippet:

var sum = 0
var i = 1
while (i <= 5) {
  sum += i
  i += 1
}
println(sum)

What is the output of this code?

A) 10
B) 15
C) 5
D) 20

Question 9: Iterating with for Loop

Analyze the Scala code below:

var product = 1
for (i <- 1 to 4) {
  product *= i
}
println(product)

What does this code print?

A) 10
B) 24
C) 12
D) 4

Question 10: Nested for Loops

Consider the following Scala code snippet that uses nested for loops:

val rows = 3
val cols = 2
for (row <- 1 to rows) {
  for (col <- 1 to cols) {
    print(s"($row,$col) ")
  }
  println()
}

What does this code print?

A) (1,1) (1,2)
(2,1) (2,2)
(3,1) (3,2)
B) (1,1) (2,1) (3,1)
(1,2) (2,2) (3,2)
C) (1,1) (1,2) (2,1) (2,2) (3,1) (3,2)
D) None of the above

Question 11: Basic if-else Logic

Consider the Scala code snippet below:

val age = 20
val canVote = if (age >= 18) {
  println("You can vote.")
  true
} else {
  println("You cannot vote.")
  false
}
println(s"Can vote: $canVote")

What is the output of this code?

A) You can vote.
Can vote: true
B) You cannot vote.
Can vote: false
C) You can vote.
Can vote: false
D) Compilation error.

Question 12: Nested if-else with Logical Operators

Review the Scala code snippet involving nested if-else and logical operators:

val age = 25
val hasLicense = true
if (age >= 18) {
  if (hasLicense) {
    println("You can drive.")
  } else {
    println("You cannot drive without a license.")
  }
} else {
  println("You are too young to drive.")
}

What is the output of this program?

A) You can drive.
B) You cannot drive without a license.
C) You are too young to drive.
D) None of the above

Question 13: if-else with Compound Conditions

Consider the following Scala code snippet:

val temperature = 30
val isRaining = false
if (temperature > 25 && !isRaining) {
  println("It's a good day for a walk.")
} else if (temperature > 25 && isRaining) {
  println("It's warm, but it's raining.")
} else {
  println("Stay indoors.")
}

What does this code print?

A) It's a good day for a walk.
B) It's warm, but it's raining.
C) Stay indoors.
D) Compilation error.

Question 14: Complex if-else with Function Calls

def checkEligibility(age: Int, hasPermit: Boolean): String = {
  if (age >= 18) {
    if (hasPermit) "Eligible" else "Not eligible: No permit"
  } else {
    "Not eligible: Too young"
  }
}

val result = checkEligibility(17, hasPermit = true)
println(result)

What is the output of this code?

A) Eligible
B) Not eligible: No permit
C) Not eligible: Too young
D) Compilation error

Question 15: Basic Pattern Matching

Consider the following Scala code snippet:

val number = 3
val result = number match {
  case 1 => "One"
  case 2 => "Two"
  case 3 => "Three"
  case _ => "Other"
}
println(result)

What is the output of this code?

A) One
B) Two
C) Three
D) Other

Question 16: Defining and Calling a Simple Function

def greet(name: String): String = {
  return "Hello, " + name + "!"
}

val greeting = greet("Alice")
println(greeting)

What is the output of this code?

A) Hello, Alice
B) Hello, Alice!
C) Greet: Alice
D) None of the above