Logical operators (&&, ||, !) in Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Kotlin code using logical AND (&&)?

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

Kotlin

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

A true

B Runtime exception

C Compilation error

D false

💡 Hint

Remember that && returns true only if both sides are true.

The && operator returns true only if both operands are true. Here, a is true but b is false, so the result is false.

❓ Predict Output

intermediate

What does this Kotlin code print using logical OR (||)?

Look at this Kotlin code. What will be printed?

Kotlin

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

A Runtime exception

B false

C Compilation error

D true

💡 Hint

|| returns true if at least one operand is true.

Both x and y are false, so x || y is false.

❓ Predict Output

advanced

What is the output of this Kotlin code using NOT (!) operator?

What will this Kotlin program print?

Kotlin

fun main() {
    val flag = true
    println(!flag)
}

A false

B true

C Compilation error

D Runtime exception

💡 Hint

The ! operator reverses the boolean value.

The ! operator negates true to false.

❓ Predict Output

advanced

What is the output of this Kotlin code combining &&, ||, and !?

Analyze this Kotlin code and determine what it prints.

Kotlin

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

A Compilation error

B false

C true

D Runtime exception

💡 Hint

Evaluate !b first, then &&, then ||.

!b is true because b is false. So a && !b is true && true = true. b && c is false && true = false. true || false = true.

🧠 Conceptual

expert

Which Kotlin expression evaluates to false?

Given these variables: val p = false, val q = true, which expression evaluates to false?

A !p && !q

B p && !q || q

C p || q && !p

D !q && p || q

💡 Hint

Evaluate each expression step by step using operator precedence.

Option A is !p && !q = true && false = false. All others evaluate to true.