Check out example codes for "kotlin". It will help you in understanding the concepts better.

Code Example 1

import java.util.*    // required import

fun randomDay() : String {
    val week = arrayOf ("Monday", "Tuesday", "Wednesday", "Thursday",
        "Friday", "Saturday", "Sunday")
    return week[Random().nextInt(week.size)]
}

fun fishFood (day : String) : String {
    return when (day) {
        "Monday" -> "flakes"
        "Wednesday" -> "redworms"
        "Thursday" -> "granules"
        "Friday" -> "mosquitoes"
        "Sunday" -> "plankton"
        else -> "nothing"
    }
}

fun feedTheFish() {
    val day = randomDay()
    val food = fishFood(day)
    println ("Today is $day and the fish eat $food")
}

fun main(args: Array<String>) {
    feedTheFish()
}

Code Example 2

val temperature = 10
val isHot = if (temperature > 50) true else false
println(isHot)

Code Example 3

val temperature = 10
val message = "The water temperature is ${ if (temperature > 50) "too warm" else "OK" }."
println(message)

Code Example 4

Kotlin is a cross-platform, statically typed, general-purpose programming language with type inference. Kotlin is designed to interoperate fully with Java, and the JVM version of its standard library depends on the Java Class Library, but type inference allows its syntax to be more concise. Kotlin mainly targets the JVM, but also compiles to JavaScript or native code (via LLVM). Language development costs are borne by JetBrains, while the Kotlin Foundation protects the Kotlin trademark.
On 7 May 2019, Google announced that the Kotlin programming language is now its preferred language for Android app developers. Since the release of Android Studio 3.0 in October 2017, Kotlin has been included as an alternative to the standard Java compiler. The Android Kotlin compiler lets the user choose between targeting Java 6 or Java 8 compatible bytecode.

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