Scala example source code file (pidigits.scala)

This example Scala source code file (pidigits.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

array, array, bigint, int, int, k, k, n, string, stringbuffer, unit, z, z

The Scala pidigits.scala source code

/* ------------------------------------------------------------------ */
/* The Computer Language Shootout                               */
/* http://shootout.alioth.debian.org/                                 */
/*                                                                    */
/* Contributed by Anthony Borla                                       */
/* ------------------------------------------------------------------ */

object pidigits
{
  def main(args: Array[String]): Unit =
  {
    val N: Int = Integer.parseInt(args(0)); var i: Int = 10

    while (i <= N)
    {
      System.out.println(pi_digits(10) + "\t:" + i)
      i = i + 10
    }

    i = i - 10

    if (i < N)
    {
      System.out.println(pi_digits(N - i) + "\t:" + N)
    }
  }

  def compose(a: Array[BigInt], b: Array[BigInt]): Array[BigInt] =
  {
    return Array(a(0) * b(0),
                 a(0) * b(1) + a(1) * b(3),
                 a(2) * b(0) + a(3) * b(2),
                 a(2) * b(1) + a(3) * b(3))
  }

  def extract(a: Array[BigInt], j: Int): BigInt =
  {
    return (a(0) * j + a(1)) / (a(2) * j + a(3))
  }

  def pi_digits(c: Int): String =
  {
    val r: StringBuffer = new StringBuffer(); var i: Int = 0

    while (i < c)
    {
      var y: BigInt = extract(Z, 3)

      while (y != extract(Z, 4))
      {
        K = K + 1; Z = compose(Z, Array(K, 4 * K + 2, 0, 2 * K + 1))
        y = extract(Z, 3)
      }

//      Z = compose(Array(10, (-y) * 10, 0, 1), Z)

      Z = compose(Array(10, y * (-10), 0, 1), Z)

      r.append(y); i = i + 1; 
    }

    return r.toString()
  }

  var K: Int = 0

  var Z: Array[BigInt] = Array(1, 0, 0, 1)
}