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.