ParityBit.scala

object ParityBit {
  type B = Int
  def f(x1: B, x2: B, x3: B, x4: B) =
    (x1 ^ x2 ^ x3,
     x1 ^ x2 ^ x4,
     x2 ^ x3 ^ x4)

  def g(x1: B, x2: B, x3: B, x4: B)(
    c1:B, c2:B, c3:B
  ) = 
    (x1 ^ x2 ^ x3 ^ c1,
     x1 ^ x2 ^ x4 ^ c2,
     x2 ^ x3 ^ x4 ^ c3)

  def problem1 = {
    println(f(1,0,1,0)) // 0 1 1
    println(f(0,1,1,0)) // 0 1 0
    println(f(1,1,0,1)) // 0 1 0
  }

  def problem2 = {
    println(g(0, 1, 0, 0)(0, 0, 0)) // 1 1 1
    println(g(0, 0, 0, 1)(0, 0, 0)) // 0 1 1
    println(g(0, 0, 0, 0)(0, 1, 0)) // 0 1 0
  }
}