Groovy example source code file (recursive.groovy)

This example Groovy source code file (recursive.groovy) 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 - Groovy tags/keywords

ack, ack, fib, fib, tak, tak

The Groovy recursive.groovy source code

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

def calc()
{
  n = Integer.parseInt(args[0])

  printf("Ack(3,%d): %d\n", n, ack(3, n))
  printf("Fib(%.1f): %.1f\n", 27.0D + n, fib(27.0D + n))

  n -= 1
  printf("Tak(%d,%d,%d): %d\n", n * 3, n * 2, n, tak(n * 3, n * 2, n))

  printf("Fib(3): %d\n", fib(3))
  printf("Tak(3.0,2.0,1.0): %.1f\n", tak(3.0D, 2.0D, 1.0D))
}

// --------------------------------

def ack(x, y)
{
  if (x == 0) return y + 1
  if (y == 0) return ack(x - 1, 1)
  return ack(x - 1, ack(x, y - 1))
}

// --------------

def fib(int n)
{
  if (n < 2I) return 1I
  return fib(n - 2I) + fib(n - 1I)
}

def fib(double n)
{
  if (n < 2.0D) return 1.0D
  return fib(n - 2.0D) + fib(n - 1.0D)
}

// --------------

def tak(int x, int y, int z)
{
  if (y < x) return tak(tak(x - 1I, y, z), tak(y - 1I, z, x), tak(z - 1I, x, y))
  return z
}

def tak(double x, double y, double z)
{
  if (y < x) return tak(tak(x - 1.0D, y, z), tak(y - 1.0D, z, x), tak(z - 1.0D, x, y))
  return z
}

calc ()