Kotlin Intermediate Quiz
Explore collections, lambdas, extension functions, data classes, and coroutines basics
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A preview of the style and depth. Try each one, then reveal the answer — or skip straight to the timed quiz.
1. What are higher-order functions?
- Complex functions
- Advanced functions
- Nested functions
- Functions taking functions as parameters or returning functions
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Answer: Functions taking functions as parameters or returning functions. Higher-order functions take functions as parameters or return functions. Example: fun operate(x: Int, op: (Int) -> Int) = op(x). Foundation of functional programming.
2. What is the apply function?
- Object builder
- Configures object and returns it
- Setup function
- Configuration function
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Answer: Configures object and returns it. apply executes block on object and returns object: person.apply { name = "John"; age = 30 }. Use for object initialization. this refers to object.
3. What is the let function?
- Block executor
- Executes lambda and returns result
- Lambda executor
- Scope function
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Answer: Executes lambda and returns result. let executes lambda with object as it and returns lambda result: name?.let { println(it.length) }. Good for null checks. it refers to object.
Frequently asked questions
How many questions are in this Kotlin quiz?+
30 questions, with a 60-minute time limit. Every question includes a written explanation of the correct answer.
Is this Kotlin quiz free?+
Yes. Every quiz on CodexQuizz is free and needs no account. You only enter a name if you choose to post your score to the leaderboard.
What level is the intermediate quiz aimed at?+
Explore collections, lambdas, extension functions, data classes, and coroutines basics
Can I use this to prepare for a Kotlin interview?+
Yes. The questions cover the topics that come up in Kotlin technical screens, and the explanations are written so that a wrong answer still teaches you the underlying concept.
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