Try-catch as an expression in Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of try-catch expression with successful try block

What is the output of this Kotlin code snippet?

Kotlin

val result = try {
    val x = 10 / 2
    "Success: $x"
} catch (e: ArithmeticException) {
    "Error"
}
println(result)

A Success: 5

B Error

C 10

D Compilation error

💡 Hint

Remember that try-catch in Kotlin can return a value from the try block if no exception occurs.

The try block executes successfully without exceptions, so the expression returns "Success: 5".

❓ Predict Output

intermediate

Output when exception is thrown in try block

What will be printed by this Kotlin code?

Kotlin

val result = try {
    val x = 10 / 0
    "Success: $x"
} catch (e: ArithmeticException) {
    "Error caught"
}
println(result)

A Success: 0

B Error caught

C ArithmeticException thrown

D Compilation error

💡 Hint

Division by zero throws an exception, so the catch block runs.

The division by zero causes an ArithmeticException, so the catch block returns "Error caught".

❓ Predict Output

advanced

Value of variable after try-catch expression with finally

What is the value of variable 'result' after running this Kotlin code?

Kotlin

val result = try {
    "Try block"
} catch (e: Exception) {
    "Catch block"
} finally {
    println("Finally block executed")
}
println(result)

A Compilation error

B Catch block

C null

D Try block

💡 Hint

Finally block runs but does not affect the returned value.

The try block returns "Try block". The finally block runs but does not change the result.

❓ Predict Output

advanced

Output when catch block throws exception in try-catch expression

What happens when this Kotlin code runs?

Kotlin

val result = try {
    val x = 10 / 0
    "Success"
} catch (e: ArithmeticException) {
    throw IllegalStateException("New exception")
}
println(result)

A IllegalStateException is thrown

B Success

C Compilation error

D ArithmeticException is caught and printed

💡 Hint

The catch block throws a new exception instead of returning a value.

The try block throws ArithmeticException, caught by catch, which then throws IllegalStateException. No value is returned.

🧠 Conceptual

expert

Why is try-catch an expression in Kotlin?

Which statement best explains why try-catch is an expression in Kotlin?

A Because it can only be used inside functions that return Unit.

B Because it only handles exceptions without returning any value.

C Because it can return a value from either the try or catch block, allowing assignment to variables.

D Because it requires a finally block to compile successfully.

💡 Hint

Think about how try-catch can be used in assignments.

In Kotlin, try-catch is an expression that returns a value from either the try or catch block, enabling concise error handling and assignment.