Replacement for c style loop with modulo - swift

Question

Since C-style for statement is deprecated and will be removed in a future version of Swift, what is the best way to achieve the following:
for var i = startIndex; i != endIndex; i = (i + 1) % arrCount {
}
(I want to iterate the array, but start from somewhere at the middle and continue until I'll reach the index I started from)
Edit:
startIndex > endIndex

Answer 1

"while" should be the best:
var i = startIndex
while i != endIndex {
i = (i + 1) % arrCount
}

Answer 2

You can shift the original array pretty easily, see this example:
let array = [3,4,5,6,7]
let startIndex = 3
let endIndex = 2
let head = array[0..<endIndex] // [3, 4]
let tail = array[startIndex..<array.count] // [6, 7]
let shiftedArray = tail + head // [6, 7, 3, 4]
for element in shiftedArray {
// do something
}

Answer 3

Here's a solution using a custom SequenceType & associated GeneratorType, as suggested by Sulthan in a comment above.
On the plus side, this sequence is really rather nicely readable and flexible. For instance:
let startIndex = 3
let endIndex = 2
let array = [3, 4, 5, 6, 7]
ModuloSequence(start: startIndex, end: endIndex, divisor: array.count).map {
array[$0]
}
On the minus side, it's rather verbose to implement (my take on it is, anyway):
struct ModuloSequenceGenerator : GeneratorType {
let end:Int, divisor:Int
private var dividend:Int?
init(start:Int, end:Int, divisor:Int) {
self.dividend = start
self.end = end
self.divisor = divisor
}
mutating func next() -> Int? {
guard let c = dividend where c != end else {
return nil
}
dividend = (c + 1) % divisor
return dividend
}
}
struct ModuloSequence : SequenceType {
let start:Int, end:Int, divisor:Int
func generate() -> ModuloSequenceGenerator {
return ModuloSequenceGenerator(start: start, end: end, divisor: divisor)
}
}