Evgeny Goldin
85 lines
2.6 KiB
Kotlin
85 lines
2.6 KiB
Kotlin
/**
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* This example implements the famous "99 Bottles of Beer" program
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* See http://99-bottles-of-beer.net/
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*
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* The point is to print out a song with the following lyrics:
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*
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* The "99 bottles of beer" song
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*
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* 99 bottles of beer on the wall, 99 bottles of beer.
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* Take one down, pass it around, 98 bottles of beer on the wall.
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*
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* 98 bottles of beer on the wall, 98 bottles of beer.
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* Take one down, pass it around, 97 bottles of beer on the wall.
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*
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* ...
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*
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* 2 bottles of beer on the wall, 2 bottles of beer.
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* Take one down, pass it around, 1 bottle of beer on the wall.
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*
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* 1 bottle of beer on the wall, 1 bottle of beer.
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* Take one down, pass it around, no more bottles of beer on the wall.
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*
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* No more bottles of beer on the wall, no more bottles of beer.
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* Go to the store and buy some more, 99 bottles of beer on the wall.
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*
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* Additionally, you can pass the desired initial number of bottles to use (rather than 99)
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* as a command-line argument
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*/
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package bottles
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fun main(args : Array<String>) {
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if (args.isEmpty) {
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printBottles(99)
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}
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else {
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try {
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printBottles(Integer.parseInt(args[0]))
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}
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catch (e : NumberFormatException) {
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System.err?.println("You have passed '${args[0]}' as a number of bottles, " +
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"but it is not a valid integral number")
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}
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}
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}
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fun printBottles(bottleCount : Int) {
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if (bottleCount <= 0) {
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println("No bottles - no song")
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return
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}
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println("The \"${bottlesOfBeer(bottleCount)}\" song\n")
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var bottles = bottleCount
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while (bottles > 0) {
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val bottlesOfBeer = bottlesOfBeer(bottles)
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print("$bottlesOfBeer on the wall, $bottlesOfBeer.\nTake one down, pass it around, ")
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bottles--
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println("${bottlesOfBeer(bottles)} on the wall.\n")
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}
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println("No more bottles of beer on the wall, no more bottles of beer.\n" +
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"Go to the store and buy some more, ${bottlesOfBeer(bottleCount)} on the wall.")
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}
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fun bottlesOfBeer(count : Int) : String =
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when (count) {
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0 -> "no more bottles"
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1 -> "1 bottle"
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else -> "$count bottles"
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} + " of beer"
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/*
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* An excerpt from the Standard Library
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*/
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// From the std.io package
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// These are simple functions that wrap standard Java API calls
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fun print(message : String) { System.out?.print(message) }
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fun println(message : String) { System.out?.println(message) }
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// From the std package
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// This is an extension property, i.e. a property that is defined for the
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// type Array<T>, but does not sit inside the class Array
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val <T> Array<T>.isEmpty : Boolean get() = size == 0
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