Step by Step solution about How to resolve the algorithm Walk a directory/Non-recursively step by step in the Kotlin programming language

This Kotlin code reads the files in a directory and filters them using a regular expression.

First, it defines a function walkDirectory that takes a directory path and a regular expression as arguments and returns a list of the files in the directory that match the regular expression.

The function then defines a regular expression r that matches all C header files beginning with 'a'.

Next, the function calls walkDirectory to get a list of all the files in the /usr/include directory that match the regular expression.

Finally, the function prints the list of files to the console.

// version 1.1.2

import java.io.File

fun walkDirectory(dirPath: String, pattern: Regex): List<String> {
    val d = File(dirPath)
    require(d.exists() && d.isDirectory())
    return d.list().filter { it.matches(pattern) }
}

fun main(args: Array<String>) {
    val r = Regex("""^a.*\.h$""")  // get all C header files beginning with 'a'
    val files = walkDirectory("/usr/include", r)
    for (file in files) println(file)
}