Number-guessing game in Kotlin

Question

I am a Java developer, and I recently gave Kotlin a try. To begin, I did a little exercise I often do when I start a new language, to verify I got the very basics: the more or less game. The code I submit there is working fine, but of course I suspect it may be too much like Java, and I would like you to point to me how I can make my code more Kotlin.

package fr.caro
import java.util.*
fun main(args: Array<String>) {
 val min = 0
 val max = 100
 var nbAttempts = 0
 val random = SplittableRandom()
 val reader = Scanner(System.`in`)
 val goal = random.nextInt(min, max)
 var userGuess: Int
 computerSays("I chose a number between $min and $max")
 do {
 nbAttempts++
 computerSays("What's your guess?")
 userGuess = reader.nextInt()
 if (userGuess > goal) computerSays("less !")
 else if (userGuess < goal) computerSays("more !")
 } while(userGuess != goal)
 computerSays("Congratulation ! You found in $nbAttempts attemps.")
}
fun computerSays(text: String) {
 println("Computer : " + text)
}

PS: I wonder if putting the min and max values in a Pair object would be a good idea?

Answer 1

When statement

You could replace:

if (userGuess > goal) computerSays("less !")
else if (userGuess < goal) computerSays("more !")

and

computerSays("Congratulation ! You found in $nbAttempts attemps.")

with:

when {
 userGuess > goal -> computerSays("less !")
 userGuess < goal -> computerSays("more !")
 userGuess == goal -> computerSays("Congratulation ! You found in $nbAttempts attemps.")
}

Extension functions

You could write computerSays as:

fun String.outputAsComputer() {
 println("Computer : " + this)
}

then to output Computer: ABC you could just write:

"ABC".outputAsComputer()

Although there are good arguments for and against this, it is more a chance to get used to extension functions

• CodingMouse: Thank you very much ! I made a new commit on this applying your tips and a friend's advice. If interested : github.com/CarolineChaudey/KotlinTraining/commit/…