Dynamic array of objects in class

Hi,

I have to write game Minesweeper in OOP way. I have classes:
Square which inherits to mineSquare, emptySquare, digitSquare and class Board which is responsible for initialize and control the game.

I have such code:

Code:

#include <iostream>
#include <typeinfo>
#include "time.h"

using namespace std;


class Square{
public:
	Square(){
		this->isShown = false;
		this->isFlagged = false;
	}
	bool getIsShown(){
		return this->isShown;
	}
	bool getIsFlagged(){
		return this->isFlagged;
	}
	void makeItShown(){
		this->isShown = true;
	}
	void makeItFlagged(){
		this->isFlagged = true;
	}
	void makeItUnflagged(){
		this->isFlagged = false;
	}
private:
	bool isShown;
	bool isFlagged;
};


class digitSquare : Square{
public:
	digitSquare(){
		value = 0;
	}
	int getValue(){
		return value;
	}
	void setValue(int value){
		this->value = value;
	}
private:
	int value;
};



class emptySquare : Square{

};

class mineSquare : public Square{
};

mineSquare type_mineSquare;
emptySquare type_emptySquare;
digitSquare type_digitSquare;

class Board{
public:
	Board(int xMax=10, int yMax=10, int amountOfMines=10){
		gameOver = false;
		this->xMax = xMax;
		this->yMax = yMax;
		this->amountOfMines = amountOfMines;
		Square*** tbl = new Square**[xMax];
		for(int i=0; i<xMax; i++){
			tbl[i] = new Square*[yMax];
		}
	}
	void init();
	void placeMines();
	bool isGameOver(){
		if(gameOver == true){
			unhideTable();
		}
		else{

		}
		return gameOver;
	}
private:
	void unhideNeighboringEmptySquares(int x, int y){
	} 
	void unhideTable(){
	}
	Square ***tbl;
	int xMax;
	int yMax;
	int amountOfMines;
	bool isMine(int x, int y);
	int countNeighboringMines(int x, int y);
	void showSquare(int x, int y);
	void flagSquare(int x, int y);
	bool gameOver;
	
};

void Board::init(){
	for(int i=0; i<xMax; i++){
		for(int j=0; j<yMax; j++){
			tbl[i][j]->makeItFlagged();
		}
	}
}

void Board::placeMines(){
	int amountOfMines = this->amountOfMines;
	for(amountOfMines; amountOfMines>0; amountOfMines--){
		srand((unsigned int)time(NULL));
		int xRandom = rand()%xMax;
		int yRandom = rand()%yMax;
		if(!isMine(xRandom,yRandom)){ 
			delete tbl[xRandom][yRandom];
			tbl[xRandom][yRandom] = new mineSquare();
		}
		else amountOfMines++;
	}
}

bool Board::isMine(int x, int y){
	if(typeid(*tbl[x][y]) == typeid(type_mineSquare)) return true;
	else false;
}
int Board::countNeighboringMines(int x, int y){

	int amountOfNeighboringMines = 0;

	if(x > 0){
		if(isMine(x-1, y)) amountOfNeighboringMines++;
		if(y > 0 && isMine(x-1, y-1)) amountOfNeighboringMines++;
		if((y < this->yMax-1) && isMine(x-1, y+1)) amountOfNeighboringMines++;
	}

	if(x < this->xMax-1){
		if(isMine(x+1, y)) amountOfNeighboringMines++;
		if(y > 0 && isMine(x+1, y-1)) amountOfNeighboringMines++;
		if((y < this->yMax-1) && isMine(x+1, y+1)) amountOfNeighboringMines++;
	}

	if(y > 0 && isMine(x, y-1)) amountOfNeighboringMines++;
	if((y < this->yMax-1) && isMine(x, y+1)) amountOfNeighboringMines++;
	return amountOfNeighboringMines;
}

void Board::showSquare(int x, int y){
	if(tbl[x][y]->getIsShown() == false) tbl[x][y]->makeItShown();
	if(isMine(x,y)) this->gameOver = true;
}

void Board::flagSquare(int x, int y){
	if(tbl[x][y]->getIsShown() == false){
		if(tbl[x][y]->getIsFlagged() == false){
			tbl[x][y]->makeItFlagged();
		}
		else{
			tbl[x][y]->makeItUnflagged();
		}
	}
}



int main(){
	Board* Game = new Board();
	Game->init(); // error
	Game->placeMines(); // i suppose i would get error here also

	system("PAUSE");
	return 0;
}

It's compiling without any problems. I get error (ImageShack Album - 2 images) when program try run method init().


Can anyone help me?

I use VC++ 2008

After a quick look:
in Board() function you instance the memory for an array of Square, but the Square itself is not instanced.
In init() the tbl in not initialized.

Less quick:

Code:

	Board(int xMax=10, int yMax=10, int amountOfMines=10){
		gameOver = false;
		this->xMax = xMax;
		this->yMax = yMax;
		this->amountOfMines = amountOfMines;
		tbl = new Square**[xMax]; // Square ***tbl : declare a temporary pointer
		for(int i=0; i<xMax; i++)
		{
			tbl[i] = new Square*[yMax];
			for (int j=0 ; j < yMax; j++)
				tbl[i][j]=new Square;
		}
	}

My init() function looks like that:

Code:

void Board::init(){
	for(int i=0; i<xMax; i++){
		for(int j=0; j<yMax; j++){
			tbl[i][j] = new Square();
		}
	}
}

Ok. I've improved the code.

Now i have another problem.

Code:

void Board::placeMines(){
	int amountOfMines = this->amountOfMines;
	for(amountOfMines; amountOfMines>0; amountOfMines--){
		srand((unsigned int)time(NULL));
		int xRandom = rand()%xMax;
		int yRandom = rand()%yMax;
		if(!isMine(xRandom,yRandom)){ // it comes into this loop
			delete tbl[xRandom][yRandom];
			tbl[xRandom][yRandom] = new mineSquare();
		}
		else amountOfMines++;
	}
}

Function placeMines() reals coordinates of the field where mine supposed to be. It should change type of cell from Square to mineSquare, but it doesn't.