Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// Basic function
fun add(a: Int, b: Int): Int {
    return a + b
}

// Single-expression function — return type inferred
fun multiply(a: Int, b: Int) = a * b

// Default parameters
fun greet(name: String, greeting: String = "Hello", punctuation: String = "!") =
    "$greeting, $name$punctuation"

// Vararg parameter
fun sumAll(vararg numbers: Int): Int {
    var total = 0
    for (n in numbers) total += n
    return total
}

// Local function — visible only inside outer function
fun processData(input: String): String {
    fun clean(s: String) = s.trim().lowercase()
    fun validate(s: String) = s.isNotEmpty()

val cleaned = clean(input)
    return if (validate(cleaned)) cleaned else "invalid"
}

fun main() {
    println(add(3, 4))            // 7
    println(multiply(6, 7))       // 42

println(greet("Alice"))                          // Hello, Alice!
    println(greet("Bob", punctuation = "."))         // Hello, Bob.
    println(greet(greeting = "Hi", name = "Carol"))  // Hi, Carol!

println(sumAll(1, 2, 3, 4, 5))   // 15

val arr = intArrayOf(10, 20, 30)
    println(sumAll(*arr))             // 60 — spread operator

println(processData("  Kotlin  "))   // kotlin
}