Нерабочий код змейки (C)

[Maledictus]

Всем доброго времени суток!
Пожалуйста, помогите понять, почему код не работает, и что с ним нужно сделать, чтобы он заработал.
Заранее спасибо

# include <iostream>
# include <windows.h>
# include <time.h>
# include <conio.h>
using namespace std;

enum keys
{
    Top = 72,
    Down = 80,
    Left = 75,
    Right = 77
};

void direction(int move_x, int move_y)
{
	
	char symbol = _getch();
	if (symbol == Top)
    {
		if(move_x != 1 || move_y != 0) 
		{ 
			move_x = -1; move_y = 0; 
		} 
	}
    if (symbol == Right)
	{
		if(move_x != 0 || move_y != -1)
		{ 
			move_x = 0; move_y = 1;
		} 
	}
	if (symbol == Down)
	{
		if(move_x != -1 || move_y != 0)
		{
			move_x = 1; move_y = 0;
		}
	}
	if (symbol == Left)
	{
		if(move_x != 0 || move_y != 1)
		{ 
			move_x = 0; move_y = -1;
		}
	}
}
void border(int a[][1000], int N, int M)
{
    system("cls");
    for (int i = 0; i <= N + 1; ++i)
	{
		for (int j = 0; j <= M + 1; ++j)
		{
			cout << (i == 0 || j == 0 || i == N + 1 || j == M + 1 ? '#' : a[i][j]) << (j <= M ? "" : "\n");
		}
	}
}
void clear (int size, int a[][1000], int x[], int y[])
{
     for (int i = 1; i <= size; ++i)
	 {
		a[x[i]][y[i]] = ' ';
	 }
}
void look (int size, int a[][1000], int x[], int y[])
{
     for (int i = 1; i <= size; ++i)
	 {
		 if (i == 1)
		 {
			a[x[i]][y[i]] = ':';
		 }
		 else
		 {
			a[x[i]][y[i]] = '@';
		 }
	 }
}
int game_over (int size, int a[][1000],  int x[], int y[],  int N, int M)
{
     for (int i = 2; i <= size; ++i)
	 {
		 if (x[1] == x[i] && y[1] == y[i])
		 {
			 return true;
		 }
 		 else if (x[1] > N)
		 {
			 return true;
		 }
		 else if (x[1] < 1) 
		 {
			 return true;
		 }
		 else if (y[1] > M)
		 {
			 return true;
		 }
		 else if (y[1] < 1)
		 {
			 return true;
		 }
		 else
		 {
			 return false;
		 }
	}
	if (game_over (size, a, x, y, N, M) == true)
	{
         cout << "You Lose!" << endl;
         system("pause");
	}
}
void next (int size, int a[][1000], int x[], int y[], int move_x, int move_y, int food_x, int food_y)
{
	 look (size, a, x, y);
	 clear (size, a, x, y);	
	 int N = 22;
	 int M = 40;
     for (int i = size; i >= 2; --i)
     {
         x[i] = x[i - 1];
         y[i] = y[i - 1];
     }
     x[1] += move_x;
     y[1] += move_y;
     if(x[1] == food_x && y[1] == food_y)
     {
        size++;
         food_x = -1;
         food_y = -1;
     }
}
int food_check(int food_x, int food_y)
{
     if(food_x == -1 && food_y == -1) 
	 {
		 return false;
	 }
	 else
	 {
		 return true;
	 }
}
void place_food (int food_x, int food_y, int a[][1000],  int x[], int y[],  int N, int M)
{
     srand(time(0));
     for (int i = 1; i <= 9; ++i)
     {
         int x = rand();
		 int y = rand();
         if (x < 0)
		 {
			 x *= -1;
		 }
         if (y < 0)
		 { 
			 y *= -1;
		 }
         x %= (N + 1);
         y %= (M + 1);
         if (x == 0)
		 {
			 ++x;
		 }
         if (y == 0)
		 {
			 ++y;
		 }
		 food_x = x;
         food_y = y;
         a[x][y] = '*';
     }
}
void main ()
{

     int size = 3;
	 const int ar_size = 500;
	 int x[ar_size];
	 int y[ar_size];
	 int a[1000][1000];
	 int move_x = 0;
     int move_y = 1;
	 int food_x = -1;
	 int food_y = -1;
	 x[1] = 1;
     y[1] = 2;
     x[2] = 1;
     y[2] = 1;
	 int N = 22;
	 int M = 40;
 
    while (true)
    {
		look (size, a, x, y);
        if (_kbhit() == true)
		{
			 direction (move_x, move_y); 
		}
		next (size, a, x, y, move_x, move_y, food_x, food_y);

	    if(food_check(food_x, food_y) == false)
		{
			place_food(food_x, food_y, a, x, y, N, M);
		}	
		border(a, N, M);

        Sleep (500);
    }
}