1. kotlin-input-output

Kotlin Input/Output

Input and output (I/O) operations are an essential part of any programming language, as they allow developers to interact with the user, files or other external sources. Kotlin provides several ways for performing I/O operations that are both efficient and easy to use.


Reading from standard input:

val input = readLine()

Writing to standard output:

println("Hello, World!")

Writing to a file:

val file = File("output.txt")
file.writeText("Hello, World!")

Reading from a file:

val file = File("input.txt")
val input = file.readText()


Reading input from the user:

fun main() {
    print("Enter your name: ")
    val name = readLine()
    println("Welcome, $name!")

Writing output to a file:

fun main() {
    val file = File("output.txt")
    val message = "Hello, World!"


Kotlin's I/O operations allow you to read data from standard input or a file, and write data to standard output or a file. By using these functions, you can interact with the user and store information on the hard drive.


Kotlin provides a set of standard functions to perform I/O operations:

  • readLine() : Reads a line of input from standard input or the console.
  • println() : Writes to the standard output.
  • File.writeText() : Creates or overwrites a file with the given text.
  • File.readText() : Returns the text content of the file.

Kotlin also provides functions for reading and writing binary data, working with sockets, and more.


You can use Kotlin's I/O functions for a variety of purposes, including:

  • Reading user input from the console.
  • Writing program output to the console.
  • Creating and writing to files.
  • Reading from and writing to network sockets.
  • Parsing and formatting data in various formats.

Important Points

  • Kotlin provides a set of standard functions for performing I/O operations.
  • These functions can be used to read user input, write program output, and work with files and sockets.
  • Kotlin also provides functions for working with binary data and other more advanced I/O tasks.


Kotlin's I/O operations provide a simple way to interact with the user and store data. With functions for reading and writing to standard input and output, as well as files and sockets, Kotlin's I/O functions make it easy to perform common I/O tasks.

Published on: