Kotlin Fundamentals

Kotlin is a statically typed language with functions, classes, collections, and control flow. You can target the JVM, Android, the web, or native platforms. The language is not a framework: a useful program also needs a target platform, a build setup, and often libraries.

Kotlin's everyday mental model is types plus explicit intent. A type describes the values an expression can hold. val states that a reference cannot be reassigned. var permits reassignment. Type inference can omit a type annotation when the initializer makes the type clear, but the inferred type remains part of the program contract.

fun greeting(name: String): String = "Hello, $name"

val message = greeting("Mina")