Ben's 18.11.15-iOS4CodeChallenge

// assumptions:
// - I will get passed an array of ints
// - ints can be positive, negative or zero
// - If only one item in the array is passed early return 0

import UIKit

// main function
func getProduct(for intArray: [Int])->[Int]{
    
    // early return [0] if only one int in the input array
    guard !(intArray.count == 1) else {return [0]}
    
    // instantiate vars
    var sumArray: [Int] = []
    var inputArray = intArray
    var sum: Int = 1
    var tempStorage: Int
    
    // loop through each value in the input array
    // remove it from the array
    // do some calculations
    // then put it back in
    for index in 0..<intArray.count{
        
        // store the value at the current index for later then remove it
        tempStorage = inputArray[index]
        inputArray.remove(at: index)
        
        for remainingItem in inputArray {
            sum *= remainingItem
        }
        // add the sum to the sumArray that will be returned
        sumArray.append(sum)
        
        // reset sum & return to input array back to its original state
        sum = 1
        inputArray.insert(tempStorage, at: index)
    }
    
    return sumArray
}

var testCases = [[1], [0], [1,2], [1,4,5,6], [1,9,6,5,2], [1,9,0,5,2],  [1,-9,6,-5,-2],  [0,-9,6,-5,-0]]

for test in testCases{
    print(getProduct(for:test))
}