Higher-Order Functions

Higher-Order Functions

Functions in F# are first-class values — you can pass them as arguments:

let apply f x = f x

let double x = x * 2
printfn $"{apply double 5}"  // 10

Anonymous functions use fun:

let result = apply (fun x -> x + 10) 5
printfn $"{result}"  // 15

List.map applies a function to every element:

let nums = [1; 2; 3; 4; 5]
let doubled = List.map (fun x -> x * 2) nums
// [2; 4; 6; 8; 10]

Your Task

Write a function sumDoubled that takes a list of integers and returns the sum of each element doubled. Use List.map and List.sum.