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   "source": [
    "# May June 2017 Question 4\n",
    "> As homework due for March 04, 2025"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Q4b\n",
    "class Node:\n",
    "    def __init__(self, data, pointer):\n",
    "        self.__Data = data\n",
    "        self.__Pointer = pointer\n",
    "    def CreateNode(data, pointer):\n",
    "        pass\n",
    "    def SetData(data):\n",
    "        self.__Data = data\n",
    "    def SetPointer(pointer):\n",
    "        self.__Pointer = pointer\n",
    "    def GetData():\n",
    "        return self.__Data\n",
    "    def GetPointer():\n",
    "        return self.__Pointer\n",
    "    ### DEBUG FN\n",
    "    def __str__(self):\n",
    "        return f\"[{self.__Data}] -> ({self.__Pointer})\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Q4 c)\n",
    "- i. A null pointer is a pointer that does not point to anything, indicating the end of a list.\n",
    "- ii. Value: -1; -1 is one less than the smallest index that can occur in the array, so it can be used to index a non-existent element."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[None, None, None, None, None, None, None, None]\n",
      "at: 0\n",
      "at: 1\n",
      "at: 2\n",
      "at: 3\n",
      "at: 4\n",
      "at: 5\n",
      "at: 6\n",
      "[0] [None] -> (1)\n",
      "[1] [None] -> (2)\n",
      "[2] [None] -> (3)\n",
      "[3] [None] -> (4)\n",
      "[4] [None] -> (5)\n",
      "[5] [None] -> (6)\n",
      "[6] [None] -> (7)\n",
      "[7] [None] -> (-1)\n"
     ]
    }
   ],
   "source": [
    "# Q4 c) iii)\n",
    "NULL_POINTER = -1\n",
    "NODE_ARRAY_LENGTH = 8\n",
    "class LinkedList:\n",
    "    def __init__(self):\n",
    "        self.__HeadPointer = -1\n",
    "        self.__FreePointer = 0\n",
    "        node_arr = [None for i in range(NODE_ARRAY_LENGTH)]\n",
    "        print(node_arr)\n",
    "        for i in range(len(node_arr) - 1):\n",
    "            print(f\"at: {i}\")\n",
    "            node_arr[i] = Node(None, i+1)\n",
    "        node_arr[len(node_arr) - 1] = Node(None, NULL_POINTER)\n",
    "        self.__NodeArray = node_arr\n",
    "    ## DEBUG FN\n",
    "    def printme(self):\n",
    "        i = 0\n",
    "        for elem in self.__NodeArray:\n",
    "            print(f\"[{i}] {elem}\")\n",
    "            i += 1\n",
    "## DEBUG CODE\n",
    "l = LinkedList()\n",
    "l.printme()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[None, None, None, None, None, None, None, None]\n",
      "at: 0\n",
      "at: 1\n",
      "at: 2\n",
      "at: 3\n",
      "at: 4\n",
      "at: 5\n",
      "at: 6\n"
     ]
    }
   ],
   "source": [
    "# Q4 c) iv)\n",
    "contacts = LinkedList()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "# ... from Q4 c) iii) ...\n",
    "def OutputListToConsole(self):\n",
    "        i = 0\n",
    "        for elem in self.__NodeArray:\n",
    "            print(f\"[{i}] {elem}\")\n",
    "            i += 1"
   ]
  }
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