Higher order function scala example

TailRecursiveSum.scala

/**
  * Created by alicana on 11/06/2016.
  */
object TailRecursiveSum {
  def square(x: Int): Int = {
    x * x
  }

  def cube(x: Int): Int = {
    x * x * x
  }

  def main(args: Array[String]) {
    println(sum(x => x,3,5))
    println(sum(square,3,5))
    println(sum(cube,3,5))
  }

  def sum(f: Int => Int,a: Int, b: Int): Int = {
    def loop(a: Int, acc: Int): Int = {
      if (a > b) acc
      else loop(a+1, f(a) + acc)
    }
    loop(a, 0)
  }
}