Penney's game: Difference between revisions

</pre>

=={{header|Kotlin}}==

<lang scala>// version 1.2.10

import java.util.Random

val rand = Random()

val optimum = mapOf(

"HHH" to "THH", "HHT" to "THH", "HTH" to "HHT", "HTT" to "HHT",

"THH" to "TTH", "THT" to "TTH", "TTH" to "HTT", "TTT" to "HTT"

)

fun getUserSequence(): String {

println("A sequence of three H or T should be entered")

var userSeq: String

do {

print("Enter your sequence: ")

userSeq = readLine()!!.toUpperCase()

}

while (userSeq.length != 3 || userSeq.any { it != 'H' && it != 'T' })

return userSeq

}

fun getComputerSequence(userSeq: String = ""): String {

val compSeq = if(userSeq == "")

String(CharArray(3) { if (rand.nextInt(2) == 0) 'T' else 'H' })

else

optimum[userSeq]!!

println("Computer's sequence: $compSeq")

return compSeq

}

fun main(args: Array<String>) {

var userSeq: String

var compSeq: String

val r = rand.nextInt(2)

if (r == 0) {

println("You go first")

userSeq = getUserSequence()

println()

compSeq = getComputerSequence(userSeq)

}

else {

println("Computer goes first")

compSeq = getComputerSequence()

println()

userSeq = getUserSequence()

}

println()

val coins = StringBuilder()

while (true) {

val coin = if (rand.nextInt(2) == 0) 'H' else 'T'

coins.append(coin)

println("Coins flipped: $coins")

val len = coins.length

if (len >= 3) {

val seq = coins.substring(len - 3, len)

if (seq == userSeq) {

println("\nYou win!")

return

}

else if (seq == compSeq) {

println("\nComputer wins!")

return

}

}

Thread.sleep(2000) // wait two seconds for next flip

}

}

</lang>

Sample game where computer goes first:

<pre>

Computer goes first

Computer's sequence: HTT

A sequence of three H or T should be entered

Enter your sequence: HHT

Coins flipped: H

Coins flipped: HH

Coins flipped: HHT

You win!

</pre>

Sample game where user goes first:

<pre>

You go first

A sequence of three H or T should be entered

Enter your sequence: HTH

Computer's sequence: HHT

Coins flipped: T

Coins flipped: TT

Coins flipped: TTT

Coins flipped: TTTT

Coins flipped: TTTTH

Coins flipped: TTTTHT

Coins flipped: TTTTHTH

You win!