Kotlin Program - Practice Test

[#191] What is the equivalent of the following Java expression in Kotlin? int x = a ? b : c

(A) val x = a ?: b, c

(B) val x = if (a) b else c

(C) val x = a ? b : c

(D) val x = if (a) b: c

Correct Answer

(B) val x = if (a) b else c

[#192] You have an enum class Signal that represents the state of a network connection. You want to print the position number of the SENDING enum. Which line of code does that? enum class Signal { OPEN, CLOSED, SENDING }

(A) println(Signal.SENDING.position())

(B) println(Signal.SENDING.hashCode())

(C) println(Signal.SENDING)

(D) println(Signal.SENDING.ordinal)

Correct Answer

(D) println(Signal.SENDING.ordinal)

[#193] What is the output of the following code? val list : List<Int> = listof(1, 2, 3)
list.add(4)
print(list)

(A) It does not compile, as listof is not known

(B) [5, 6, 7]

(C) It does not compile as List has no add method

(D) [1, 2, 3, 4]

Correct Answer

(C) It does not compile as List has no add method

[#194] What does the following code print? val listA = mutableListOf(1, 2, 3)
val listB = listA.add(4)
print(listB)

(A) true

(B) [1, 2, 3, 4]

(C) Nothing, there is a compile error

(D) Unit

Correct Answer

(A) true

[#195] What is the difference between the declarations of COLOR and SIZE? class Record{
companion object {
const val COLOR = "Red"
val SIZE = "Large"
}
}

(A) Since COLOR and SIZE are both immutable, they are identical internally

(B) Both are immutable, but the use of the keyword const makes COLOR slower and less space efficient than SIZE

(C) const makes COLOR faster, but not compatible with Java. Without const, SIZE is still compatible with Java

(D) Both are immutable, but the use of the keyword const makes COLOR faster and more space efficient than SIZE

Correct Answer

(D) Both are immutable, but the use of the keyword const makes COLOR faster and more space efficient than SIZE

Kotlin Program - Study Mode

[#191] What is the equivalent of the following Java expression in Kotlin? int x = a ? b : c

Correct Answer

[#192] You have an enum class Signal that represents the state of a network connection. You want to print the position number of the SENDING enum. Which line of code does that? enum class Signal { OPEN, CLOSED, SENDING }

Correct Answer

[#193] What is the output of the following code? val list : List<Int> = listof(1, 2, 3) list.add(4) print(list)

Correct Answer

[#194] What does the following code print? val listA = mutableListOf(1, 2, 3) val listB = listA.add(4) print(listB)

Correct Answer

[#195] What is the difference between the declarations of COLOR and SIZE? class Record{ companion object { const val COLOR = "Red" val SIZE = "Large" } }

Correct Answer

[#193] What is the output of the following code? val list : List<Int> = listof(1, 2, 3)
list.add(4)
print(list)

[#194] What does the following code print? val listA = mutableListOf(1, 2, 3)
val listB = listA.add(4)
print(listB)

[#195] What is the difference between the declarations of COLOR and SIZE? class Record{
companion object {
const val COLOR = "Red"
val SIZE = "Large"
}
}