Foodgame c++

#include <iostream>
#include <string>
#include <ctime>
#include <cstdlib>

using namespace std;

class GameObject {
protected:
	int distance;
	int x, y;

public:
	GameObject(int startX, int startY, int distance)
	{
		this->x = startX; this->y = startY;
		this->distance = distance;
	}

	virtual ~GameObject() {};
	virtual void move() = 0;
	virtual char getShape() = 0;
	int getX() { return x; }
	int getY() { return y; }
	bool collide(GameObject* p) {
		if (this->x == p->getX() && this->y == p->getY())
			return true;
		else
			return false;
	}
};


class Human : public GameObject {
public:
	Human(int x, int y, int dis) :GameObject(x, y, dis) {}
	void move();
	char getShape() { return'H'; }
};


void Human::move()
{
	string key;
	for (;;) {
		cout << "left(a), down(s), up(w), right(d)" << endl;
		cin >> key;
		if (key == "a") {
			if (y != 0) {
				y -= distance;
				break;

			}
			else cout << "cant move" << endl;
		}
		else if (key == "s") {
			if (x != 19) {
				x += distance;
				break;
			}
			else cout << "cant move" << endl;
		}
		else if (key == "w") {
			if (x != 0) {
				x -= distance;
				break;
			}
			else cout << "cant move" << endl;
		}
		else if (key == "d") {
			if (y != 19) {
				y += distance;
				break;
			}
			else cout << "cant move" << endl;
		}
		else
			cout << "error" << endl;
	}
}

class Monster :public GameObject
{
public:
	Monster(int x, int y, int dis) :GameObject(x, y, dis) {
		srand((unsigned)time(0));
	}
	void move();
	char getShape() { return'M'; }

};

void Monster::move() {
	for (;;) {
		int n = rand() % 4;
		if (n == 0)
		{
			if (y > 1) {
				y -= distance;
				break;
			}
		}
		else if (n == 1)
		{
			if (x < 18)
			{
				x += distance;
				break;
			}
		}
		else if (n == 2)
		{
			if (x > 1)
			{
				x -= distance;
				break;
			}
		}
		else 
		{
			if (y < 18)
			{
				x += distance;
				break;
			}
		}
	}
 }

class Food :public GameObject {
public:
	Food(int x, int y, int dis) :GameObject(x, y, dis) {}
	void move();
	char getShape() { return'@'; }
};

void Food::move() {
	for (;;) {
		int n = rand() % 4;
		if (n == 0)
		{
			if (y != 0) {
				y -= distance;
				break;
			}
		}
		else if (n == 1)
		{
			if (x != 19)
			{
				x += distance;
				break;
			}
		}
		else if (n == 2)
		{
			if (x != 0)
			{
				x -= distance;
				break;
			}
		}
		else
		{
			if (y != 19)
			{
				x += distance;
				break;
			}
		}
	}
}

class Game
{
	string board[20][20];
	Human* h = new Human(0, 0, 1);
	Monster* m = new Monster(5, 7, 2);
	Food* f = new Food(8, 10, 1);

public: 
	Game() {
		srand((unsigned)time(0));
		cout << "Human food game start" << endl << endl;

		for (int i = 0; i < 20; i++)
		{
			for (int j = 0; j < 20; j++)
				board[i][j] = "-";
		}
	}
	~Game() {
		delete h; delete m; delete f;
	}

	void game();

	void clr1() {
		board[h->getX()][h->getY()] = "-";
		board[m->getX()][m->getY()] = "-";
	}

	void clr2()
	{
		board[f->getX()][f->getY()] = "-";
	}

	void setXY() {
		board[h->getX()][h->getY()] = h->getShape();
		board[m->getX()][m->getY()] = m->getShape();
		board[f->getX()][f->getY()] = f->getShape();

	}

	void show() {
		for (int i = 0; i < 20; i++) {
			for (int j = 0; j < 20; j++)
				cout << board[i][j];
			cout << endl;
		}
	}

};

void Game::game()
{
	int count = 0, gamecount = 0;
	for (;;)
	{
		setXY();
		show();
		clr1();
		h->move(); m->move();
		int n = rand();
		cout << endl;

		if (n % 2 == 0 && count < 2 && gamecount < -3) {
			clr2();
			f->move();
			++count;
		}

		if (gamecount > 3 && count < 2) {
			clr2();
			f->move();
			++count;
		}
		if (f->collide(h)) {
			setXY();
			board[f->getX()][f->getY()] = "H";
			show();
			cout << "Human is winner" << endl;
			break;
		}
		else if (h->collide(m)) {
			setXY();
			board[f->getX()][f->getY()] = "M";
			show();
			cout << "Monster is winner" << endl;
			break;
		}
		else if (f->collide(m)) {
			setXY();
			board[f->getX()][f->getY()] = "M";
			show();
			cout << "Monster is winner" << endl;
			break;
		}
		++gamecount;

		if ((gamecount % 5) == 0) {
			count = 0;
			gamecount = 0;
		}
	}
}

int main()
{
	Game* g = new Game;
	g->game();
	delete g;
	Game();
}