Boolean type and logical operators in Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Kotlin code using logical operators?

Consider the following Kotlin code snippet. What will it print?

Kotlin

fun main() {
    val a = true
    val b = false
    val c = a && !b || b
    println(c)
}

A true

B false

C Compilation error

D Runtime exception

💡 Hint

Remember that !b means 'not b', and && has higher precedence than ||.

The expression evaluates as (a && (!b)) || b. Since a is true and b is false, !b is true. So true && true is true, and true || false is true.

❓ Predict Output

intermediate

What does this Kotlin code print with mixed logical operators?

Analyze the output of this Kotlin program:

Kotlin

fun main() {
    val x = false
    val y = true
    val result = x || y && false
    println(result)
}

A true

B false

C Compilation error

D Runtime exception

💡 Hint

&& has higher precedence than || in Kotlin.

The expression is x || (y && false). y && false is false, so x || false is false || false, which is false.

🔧 Debug

advanced

What error does this Kotlin code raise?

Examine this Kotlin snippet and identify the error it produces when compiled or run:

Kotlin

fun main() {
    val a = true
    val b = false
    val c = a && b ||
    println(c)
}

A No error, prints false

B TypeError

C Unresolved reference error

D SyntaxError

💡 Hint

Look carefully at the expression assigned to c.

The expression ends abruptly with '||' without a right-hand operand, causing a syntax error.

❓ Predict Output

advanced

What is the output of this Kotlin code using logical negation and equality?

What will this Kotlin program print?

Kotlin

fun main() {
    val a = true
    val b = false
    val c = !(a == b) && (a || b)
    println(c)
}

A Compilation error

B false

C true

D Runtime exception

💡 Hint

Evaluate the equality first, then apply negation and logical operators.

a == b is false, so !(false) is true. a || b is true. true && true is true.

🧠 Conceptual

expert

How many items are in the resulting list after filtering with logical operators?

Given this Kotlin code, how many elements does the list 'filtered' contain?

Kotlin

fun main() {
    val numbers = listOf(1, 2, 3, 4, 5, 6)
    val filtered = numbers.filter { it % 2 == 0 && it > 3 || it == 1 }
    println(filtered.size)
}

A 4

B 3

C 2

D 5

💡 Hint

Remember that && has higher precedence than || in Kotlin filter conditions.

The filter condition is (it % 2 == 0 && it > 3) || it == 1. Even numbers greater than 3 are 4 and 6, plus 1. So filtered list is [1,4,6], size 3.