When without argument in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a when expression without an argument in Kotlin?

A when without an argument works like an if-else if chain. Each branch checks a condition that returns a Boolean.

beginner

How do you write a when expression without an argument?

You write when { condition1 -> action1; condition2 -> action2; else -> defaultAction }. Each condition is a Boolean expression.

intermediate

What happens if none of the conditions in a when without argument match and there is no else branch?

The program throws a kotlin.NoWhenBranchMatchedException at runtime because no branch was matched.

beginner

Can when without argument replace multiple if-else if statements?

Yes, it can make code cleaner and easier to read by grouping conditions in one expression.

beginner

Example: What does this code print?<br>

when {
  5 > 10 -> println("Greater")
  5 < 10 -> println("Smaller")
  else -> println("Equal")
}

It prints Smaller because 5 < 10 is true, so that branch runs.

What does a when without argument check in Kotlin?

A The type of an object

B Boolean conditions in each branch

C The value of a variable

D Nothing, it always runs the first branch

Without an argument, when checks each branch's Boolean condition.

What keyword is required to handle unmatched cases in a when without argument?

A finally

B default

C catch

D else

The else branch handles all unmatched cases.

What happens if no condition matches and there is no else branch in a when without argument?

A The program continues silently

B The first branch runs anyway

C A runtime exception is thrown

D The program crashes at compile time

A NoWhenBranchMatchedException is thrown at runtime.

Which of these is a valid when without argument branch?

A x == 5 -> println("Five")

B 5 -> println("Five")

C "hello" -> println("Hello")

D else if x == 5 -> println("Five")

Branches must be Boolean conditions like x == 5.

Why use when without argument instead of if-else if?

A It groups conditions clearly in one expression

B It can check multiple variables at once

C It is faster to run

D It requires less code to write

when groups conditions clearly, improving readability.

Explain how a when expression without argument works in Kotlin and give a simple example.

Think about how you check multiple true/false questions one by one.

What is the role of the else branch in a when without argument? What happens if it is missing?

Consider what happens if no condition is true.