Logical operators (&&, ||, !) in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the logical AND operator (&&) do in Kotlin?

The logical AND operator (&&) returns true only if both conditions on its sides are true. If either condition is false, it returns false.

beginner

Explain the logical OR operator (||) in Kotlin.

The logical OR operator (||) returns true if at least one of the conditions is true. It returns false only if both conditions are false.

beginner

What is the purpose of the logical NOT operator (!) in Kotlin?

The logical NOT operator (!) reverses the value of a boolean expression. If the expression is true, ! makes it false, and vice versa.

beginner

Given: val a = true, val b = false, what is the result of a && b?

The result is false because the AND operator requires both sides to be true, but b is false.

intermediate

How does Kotlin evaluate the expression: !(true || false)?

First, true || false evaluates to true. Then, !true becomes false. So the whole expression is false.

What is the result of true && false in Kotlin?

A true

B false

C null

D Compilation error

The AND operator returns true only if both sides are true. Here, one side is false, so the result is false.

Which operator returns true if at least one condition is true?

A ||

B !

C ==

D &&

The OR operator (||) returns true if any one of the conditions is true.

What does the ! operator do to a boolean value?

A Leaves it unchanged

B Converts it to a number

C Throws an error

D Reverses it (true to false, false to true)

The NOT operator (!) reverses the boolean value.

What is the result of !(false && true)?

A null

B false

C true

D Compilation error

false && true is false, then !false is true.

Which of these expressions is true?

A true || false

B true && false

C !true

D false || false

true || false is true because OR returns true if any side is true.

Describe how the logical AND (&&) and OR (||) operators work in Kotlin with simple examples.

Think about when you want both conditions to be true versus when one is enough.

Explain the effect of the logical NOT operator (!) on a boolean expression.

It flips the meaning of a condition.