First Program in Kotlin


Overview

  • Kotlin is a general purpose, open source, the statically-typed programming language that runs on the JVM (Java virtual machine) infrastructure.
  • It is focused on Concise, simple, very easy to understand, safety, and library support. 
  • Kotlin is an official language on Android
  • Kotlin is a fully supported programming language on Android via Android Studio 3.0 

Here, Kotlin first program is a simple program that prints output "Hello, World! - www.littledrops.net" on the screen. 

Setting up the Kotlin

Syntax

fun main(args: Array<String>) {
    // Main Program Code 
}

Simple Kotlin Example Program

// My First Program
fun main(args: Array<String>) {
    println("Hello, world! - www.littledrops.net")
}

Sample Output

Hello, world! - www.littledrops.net

How does Kotlin program work?

1. Comment line

// My First Program

The text preceded by // is a comment line in Kotlin (similar to C, C++, and Java). Comments are neglected by Kotlin compiler. Comments are designed for the better understanding of code and functionality and changes in the program. 

2. Main Function

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

This is the main function of the kotlin main function is mandatory in every Kotlin program like C and C++. It is the entry point of any Kotlin program.The Kotlin compiler begins executing kotlin program code from the main function.

3. Command Line Arguments  (args: Array<String>)

The function takes the array of strings as a parameter and returns Unit which is equivalent to String args[] in java.

4. println

println("Hello, world! - www.littledrops.net")

The println() function prints the given string inside the double quotation with a new line to the screen or output stream. The above line just prints Hello, world! - www.littledrops.net to the screen/stream.