Reading line by line using InputReader

Sometimes we need to read the contents of a file line by line and process it. This is easily done by reading a file line by line using the InputReader. Let's see how.

Getting ready

You need to install a preferred development environment that compiles and runs Kotlin. You can also use the command line for this purpose, for which you need the Kotlin compiler installed along with JDK. You can also use IntelliJ IDEA for the development environment.

How to do it…

In the following steps, we will learn how to make use of the InputReader class to read the text line by line:

1. Let's start with attaching the InputStream to the file and going line by line on the contents, like this:

import java.io.File
import java.io.InputStream

fun main(args: Array<String>) {
    val listOfLines = mutableListOf<String>()
    val inputStream: InputStream =  File("example2.txt").inputStream()
    inputStream.reader().useLines { lines -> lines.forEach { listOfLines.add(it...