Input & Output

Getting information out of your program and reading input from the user — that's how your code actually talks to the world.

`println()` and `print()`

println() prints text and moves to a new line. print() stays on the same line.


fun main() {
  print("Hello ")
  print("from ")
  println("Kotlin")
  println("This is on a new line")
}

This will output: Hello from Kotlin then This is on a new line underneath.

readLine() reads whatever the user types as a String. You can then convert it if you need a number.


fun main() {
  print("What's your name? ")
  val name = readLine()
  println("Nice to meet you, $name!")
}

Since readLine() always returns a String, use toInt() or toDouble() to convert.


fun main() {
  print("Enter a number: ")
  val input = readLine()
  val number = input!!.toInt()
  println("Double that is ${number * 2}")
}

The !! tells Kotlin "I know this might be null, but I'm sure it's not." We'll talk more about null safety later.

Which function prints text and adds a new line in Kotlin?

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