Higher-Order Functions

Higher-Order Functions

Functions can take other functions as parameters:

def applyTwice(f: Int => Int, x: Int): Int = f(f(x))

println(applyTwice(x => x * 2, 3))  // 12

Returning Functions

def multiplier(factor: Int): Int => Int = x => x * factor

val triple = multiplier(3)
println(triple(5))  // 15

reduce

reduce is like foldLeft but uses the first element as the starting value:

val product = List(1, 2, 3, 4).foldLeft(1)((acc, x) => acc * x)
println(product)  // 24

Your Task

Write a function product that takes a List[Int] and returns the product of all elements using foldLeft. An empty list should return 1.