Scala recursive function values definition

Question

This non compiling code on defining a recursive function value,

val factorial = (n:Int) => if (n < 1) 1 else n * factorial(n-1)

produces an error message such as

recursive value factorial needs type

How to declare the return type ?

Answer 1

Like this

val factorial: Int => Int = (n:Int) => if (n<1) 1 else n*factorial(n-1)

In fact, I would write it like so:

def factorial(n: Int): Int = if (n < 1) 1 else n * factorial(n-1)