Scala遞回函式

遞回在純功能程式設計中起著重要作用，Scala支援遞回函式。 遞迴表示一個函式可以重複呼叫自身。

嘗試以下程式，它是一個很好的遞迴範例，它計算給定引數(數位)的階乘。

範例

object Demo {
   def main(args: Array[String]) {
      for (i <- 1 to 10)
         println( "Factorial of " + i + ": = " + factorial(i) )
   }

   def factorial(n: BigInt): BigInt = {  
      if (n <= 1)
         1  
      else    
      n * factorial(n - 1)
   }
}

將上述程式儲存在原始檔：Demo.scala中，使用以下命令編譯和執行此程式。

$ scalac Demo.scala
$ scala Demo

Factorial of 1: = 1
Factorial of 2: = 2
Factorial of 3: = 6
Factorial of 4: = 24
Factorial of 5: = 120
Factorial of 6: = 720
Factorial of 7: = 5040
Factorial of 8: = 40320
Factorial of 9: = 362880
Factorial of 10: = 3628800