Write and read from/to the console in Kotlin is very simple, using the following methods: println(), print() and readln().

Write

To write any value to the console use the print() or the println() method, defined in kotlin.io.

Example 1:

fun main() {
    println("Hello, World!")
    // Output: Hello, World!
}

Example 2:

fun main() {
    println("Output 1")
    println("Output 2")
    // Output: Output1
    //         Output2
}

Example 3:

fun main() {
    print("Hello, World!")
    // Output: Hello, World!
}

Example 4:

fun main() {
    print("Output 1")
    print("Output 2")
    // Output: Output1Output2
}

CONCLUSION: println() prints a line break after your string.

TIP: If you pass another value, for example a java.io.File, println() and print() prints the return value of the toString() method.

INFO: println()/print() only call the System.out.println()/System.out.print() method.

Read

To read any string, use the readln() method, defined in kotlin.io.

Example 1:

fun main() {
    print("Your name: ")
    val input = readln()
    println("Hello, $input!")
}

Example 2:

fun main() {
    print("Whats your name? ")
    val name = readln()
    print("How old are you? ")
    val age = readln()
    println("Hello $name, you are $age years old!")
}

-