convertArray.swift

func convertArray(array: [Int]) -> [String]? {
  
  // Nothing to do. Exiting.
  guard array.count > 0 else { return nil}
  
  // Things to convert.
  var stringArray = [String]()
  
  for int in array {
    let string = "\(int)"
    stringArray.append(string)
  }
  
  return stringArray
}

let intArray = [0, 1, 2, 3, 4]
let convertedInts = convertArray(intArray)