chapter2.scala

object chapter2 {

	def simplefib(n: Int): Int =
		if (n <= 1) n
		else simplefib(n - 1) + simplefib(n - 2)

	def fib(n: Int): Int = {
		@annotation.tailrec
		def loop(i: Int, acc: Int, x: Int): Int =
			if (i <= 0) acc
			else loop(i - 1, x, acc + x)

		loop(n, 0, 1)
	}

	def isSorted[A](as: Array[A], ordered: (A,A) => Boolean): Boolean = {
		@annotation.tailrec
		def loop(i: Int, acc: Boolean): Boolean =
			if (i < as.size - 1 && acc) loop(i + 1, ordered(as(i), as(i + 1)))
			else acc
		loop(0, true)
	}

	def curry[A,B,C](f: (A, B) => C): A => (B => C) = a => b => f(a, b)

	def uncurry[A,B,C](f: A => B => C): (A, B) => C = (a, b) => f(a)(b)

	def compose[A,B,C](f: B => C, g: A => B): A => C = a => f(g(a))

}