Kotlin Control Flow


Control Flow

Basic Usage

If Expression

if can be used in same way as in other programming languages

var min: Int if (a < b) { min = a } else { min = b }

else can also be omitted if not needed

if (a < b) { print("a is smaller") }

When Expression

when keyword is replacing usual switch-case expression
The else branch is evaluated if none of the other branch conditions are satisfied
It has powerfull matching branches which support complex evaluations of input argument

when (obj) { 1 -> "One" 1, 2 -> "One or Two" "Hello" -> "Greeting" is Long -> "Long" !is String -> "Not a string" else -> "Unknown" }

Range evaluation

when (x) { in 1..100 -> print("x is in the range") in validNumbers -> print("x is valid") !in 10..200 -> print("x is outside the range") else -> print("none of the above") }

For Loops

for loop can iterate through anything that provides and interator, using in operator

val fruits = listOf("apple", "banana", "kiwi") for (fruit in fruits) { println(fruit) }

Iterating through range of numbers

for (i in 1..5) { println(i) }

While Loops

while and do..while are used like in most programming languages

while (a > 0) { a-- } do { val b = provideData() } while (b != null)

Break and continue keywords

Used like in most other programming languages

Resources

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