HackerRank - 30 Days of Code - Day 19: Interfaces : Swift solution suggestion

day-19-interfaces.swift

import Foundation

protocol AdvancedArithmetic {
    func divisorSum(_ n: Int) -> Int
}

class Calculator: AdvancedArithmetic {

    func divisorSum(_ n: Int) -> Int {
        var result = n
        for divisor in 1..<n {
            result += n % divisor == 0 ? divisor : 0
        }
        return result
    }

}

let myCalculator: AdvancedArithmetic = Calculator()

if let calculator = myCalculator as? AdvancedArithmetic {
    print("I implemented: AdvancedArithmetic")
    print(calculator.divisorSum(Int(readLine()!)!))
}