How to find the largest element in a list of integers recursively?

Question

I\'m trying to write a function which will recursively find the largest element in a list of integers. I know how to do this in Java, but can\'t understand how to do this at Sca

Answer 1

If you want functional approach to this problem then use reduceLeft:

def max(xs: List[Int]) = {
  if (xs.isEmpty) throw new NoSuchElementException
  xs.reduceLeft((x, y) => if (x > y) x else y)
}

This function specific for list of ints, if you need more general approach then use Ordering typeclass:

def max[A](xs: List[A])(implicit cmp: Ordering[A]): A = {
  if (xs.isEmpty) throw new NoSuchElementException
  xs.reduceLeft((x, y) => if (cmp.gteq(x, y)) x else y)
}   

reduceLeft is a higher-order function, which takes a function of type (A, A) => A, it this case it takes two ints, compares them and returns the bigger one.