难以理解功能

基本上我有一个藏宝图，用户正在尝试找到宝藏。藏宝图应该是用2D阵列打印的。我们应该调用函数来随机化宝藏和开始位置，对于用户的每个回合，等等。

我不知道如何在函数中声明我的变量。每次我写函数时都必须重新声明，但我的教授说我应该只声明一次？

我教授编写的主要功能：

int main() 
{
   char Map[ROWS][COLS];
   int TreasureR, TreasureC; 
   int StartR, StartC; 
   int Row, Col;   
   int NumMoves = 0;          // The number of player moves
   bool Winner = false;
   bool Quit = false;
   cout << "This homework was written by Savanna Bruce.n";
   cout << "You are stranded on a desert island with no idea how to survive.n";
   cout << "Fortunately, there are tools to survive and a hidden Treasure!n";
   cout << "Find the Treasure!!!nnn";

   // Seed the random number variable
   srand (time(NULL));
   // Start a New Game or Continue an Old one
   InitMap (Map);
   // Add code to place the treasure and start
   Random();
   // Add code to play the game
   PlayTurn();
   // Print the Map, hide the Treasure
   PrintMap(Map, false);
   return 0;
}

到目前为止，我拥有的功能：

// Name: InitMap
// Description: Initialize the Map with all EMPTY cells
// Return: Nothing
// ---------------------------------------------------
void InitMap(char Map[][COLS])
{
    Map = 0;
}
// ---------------------------------------------------
void Random()
{
    int TreasureC, TreasureR;
    int StartC, StartR;
    int Col, Row;
    // Set the location of the treasure chest
    TreasureC = rand() % COLS;   // set to a value in range 0..XDIM-1
    TreasureR = rand() % ROWS;   // set to a value in range 0..YDIM-1
    // Set the starting location of the player
    StartC = rand() % COLS;      // set to a value in range 0..XDIM-1
    StartR = rand() % ROWS;      // set to a value in range 0..YDIM-1
    Col = StartC;
    Row = StartR;
}
void PrintMap(const char Map[][COLS], const bool showTreasure) 
{
    int TreasureR = 0;
    int TreasureC = 0;
    for (int row = 0; row < ROWS; row++)
    {
       for (int col = 0; col < COLS; col++)
       {
           if ((row == TreasureR && col == TreasureC) && showTreasure == true)
               cout << TREASURE;
           else
               cout << EMPTY;
       }
    cout <<  endl;
    }
}

全局变量：

const int FAST = 3;
const int SLOW = 5;
const int COLS = 20;                // For MAP Size
const int ROWS = 10;                // For MAP Size
const int MAX_ROW = ROWS - 1;       // valid locations are 0..ROWS - 1
const int MAX_COL = COLS - 1;       // valid locations are 0..COLS - 1
const string FILENAME = "Map.txt";  // File to save/load Map from
// Cell types - The Map can have any of these
// characters at a location on a Map.
const char START = 'S';
const char PLAYER = 'P';
const char TREASURE = 'T';
const char EMPTY = '*';
const char VISITED = 'X';

有人可以告诉我这些是否正确，以及我是否应该一遍又一遍地声明我的变量？