let key: Int = 11
var numbers: [Int] = [9, 15, 91]
let idx: Int = BinarySearch.binaryIndex(numbers, i: key) // 1
if idx <= numbers.count || numbers[idx] != key { // assert that index is real, and avoid dups
	numbers.insert(key, at: idx)
}
print(numbers) // [9, 11, 15, 91]

var strings: [String] = ["a", "b", "d", "e", "g", "j", "m"]
let idx: Int = BinarySearch.binaryIndex(strings, i: "f") // 4
strings.insert("f", at: idx)
print(strings) // ["a", "b", "d", "e", "f", "g", "j", "m"]

let numbers: [Int] = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67]
guard let idx: Int = BinarySearch.binarySearch(numbers, key: 43) else { Swift.print("no result"); return }// output: 13 which is the index of where the key is
Swift.print("idx:  \(idx)") // 13

let strings: [String] = ["a", "b", "c", "d", "e", "f", "g"]
guard let idx: Int = BinarySearch.binarySearch(strings, key: "e") else { Swift.print("no result"); return }
Swift.print("idx:  \(idx)") // 4