C++ spiralno pisanje v array

namespace SpiralArray
{
    class Program
    {
        static void Main(string[] args)
        {
            int[,] arr = new int[21,21];
            arr[10, 10] = 1;
            int value;
            int[] tmp = new int[] {10, 10};
            System.Random r = new System.Random();
            do
            {
                value = arr[tmp[0], tmp[1]];
                tmp = NextPosition(tmp[0], tmp[1]);
                arr[tmp[0], tmp[1]] = value + r.Next(1, 3);
            } while (!(tmp[0] == 0 && tmp[1] == 20));
        }

        static int[] NextPosition(int x, int y)
        {
            //začetna pozicija, predvidevam da gre gor.
            if (x == 10 && y == 10) return new int[] {--x, y};

            //preveri če si v enem izmed kotov spirale
            if (x == y) //levo zgoraj ali desno spodaj?
                return x < 10 ? new int[] {++x, y} : new int[] {--x, y};
            if (x + y == 20)
                return x < 10 ? new int[] {--x, y} : new int[] {x, ++y};

            //preveri če je x ali y 10
            if (x == 10)
                return x < y ? new int[] {--x, y} : new int[] {++x, y};
            if (y == 10)
                return x < y ? new int[] {x, --y} : new int[] {x, ++y};

            // preostalo premikanje
            if (x < 10 && y < 10)
                return x < y ? new int[] {x, --y} : new int[] {++x, y};
            if (x < 10 && y > 10)
                return x + y > 20 ? new int[] {--x, y} : new int[] {x, --y};
            if (x > 10 && y < 10)
                return x + y > 20 ? new int[] {x, ++y} : new int[] {++x, y};
            return x < y ? new int[] {--x, y} : new int[] {x, ++y};
        }
    }
}

const int WIDTH = 21;
const int HEIGHT = 21;
const int RPT = 2;

typedef unsigned int UINT;
typedef UINT field_t [HEIGHT][WIDTH];
typedef struct
{
	UINT w;
	UINT h;
} loc_t;
typedef enum {UP, DOWN, LEFT, RIGHT} turn_t;

void Display (field_t field)
{
	for (int h = 0; h < HEIGHT; h++) {
		cout << '|';
		for (int w = 0; w < WIDTH; w++) {
			cout.width(2);
			cout << field[h][w] << '|';
		}
		cout << endl;
	}
	cout << endl;
}

int main(int argc, char* argv[])
{
	field_t field = {0};
	loc_t loc = {10, 9};
	turn_t turn = DOWN;
	UINT nn = 1;

	UINT STP = 2;
	UINT stp = STP;
	UINT rpt = RPT;

	for (int i = 0; i < (WIDTH*HEIGHT); i++) {
		switch(turn) {
		case DOWN:
			field[++loc.h][loc.w] = nn;
			break;
		case UP:
			field[--loc.h][loc.w] = nn;
			break;
		case LEFT:
			field[loc.h][--loc.w] = nn;
			break;
		case RIGHT:
			field[loc.h][++loc.w] = nn;
			break;
		}

		Display(field);

		--stp;
		if (stp == 0) {
			--rpt;
			if (rpt == 0) {
				++STP;
				++nn;
				rpt = RPT;
			}
			stp = STP-1;
			if (turn == DOWN) turn = RIGHT;
			else if (turn == RIGHT) turn = UP;
			else if (turn == UP) turn = LEFT;
			else if (turn == LEFT) turn = DOWN;
		}

	}

	return 0;
}