iOS4CodeChallenge-18.11.08

import UIKit

func sumOf35Multiples(_ number: Int) -> Int {
    
    // Check to make sure some joker didn't put zero or negative
    // or a really big number. return -1 if it might be a joker
    guard number > 0, number < 100000 else { return -1 }
    
    // instantiate local vars
    var matches: Array<Int> = []
    var sum = 0
    
    // check if the number mod 3 or mod 5 is zero
    // if so, add to the matches list
    for index in 1..<number {
        
        if(index % 3 == 0 || index % 5 == 0){
            matches.append(index)
        }
    }
    
    // sum the values in matches int array
    for match in matches {
        sum += match
    }
    return sum
    
}

let testCases = [10,-1,2,200,30,-2,1000,200000]

for test in testCases{
    print(sumOf35Multiples(test))
}

print("The sum below 1000 is equal to: \(sumOf35Multiples(1000))")

Looks great Ben! I like how you've solved the problem and how much of your thought process I can see. I also like that you've bounded it a little bit, in case someone tries to use too big or too small of a number. If this were a real implementation somewhere, I would just suggest that you document why you might sometimes return a -1, so it doesn't break some program that relies on sumOf35Multiples(100001). You could also create the lower bound by using UInt instead of Int and starting your for loop at 0. Overall though, great job!