/// 取出棧底的數
func getAndRemoveLastElement(_ items: inout [Int]) -> Int {
    
    let value = items.remove(at: 0)
    if (items.isEmpty) {
        return value
    }
    let last = getAndRemoveLastElement(&items)
    items.insert(value, at: 0)
    return last
}

func reverse(_ items: inout [Int]) {
    
    if (items.isEmpty) {
        return
    }
    let value = getAndRemoveLastElement(&items)
    reverse(&items)
    // 逆序把棧底的數放回數組中，完成逆序
    items.append(value)
    
}

var data = [1, 2, 3, 4, 5]
reverse(&data)
print(data)