Kotlin Playground

The fastest way to try Kotlin code without the need to install any software is Kotlin Playground (https://try.kotlinlang.org). We can run Kotlin code there using JavaScript or JVM Kotlin implementations and easily switch between different Kotlin versions. All the code examples from the book that does not require Android framework dependencies and can be executed using Kotlin Playground.

The main function is the entry point of every Kotlin application. This function is called when any application starts, so we must place code from the book examples in the body of this method. We can place code directly or just place a call to another function containing more Kotlin code:

    fun main(args: Array<String>) { 
        println("Hello, world!") 
    }