Find factorial of the int number in swift

Factorial.swift

func factorial(of number: Int) -> Int {
    if number == 1 {
        return 1
    } else {
        return number * factorial(of: number - 1)
    }
}

let val = 5
let result = factorial(of: val)

print("The factorial of \(val) is \(result)")
// prints: The factorial of 5 is 120