// ¸ó½ºÅÍ À̵¿

void move_monster() {
    for (int i = 0; i < MONSTER_COUNT; i++) {

        int prev_y = monster_y[i], prev_x = monster_x[i];

        // ÇöÀç À§Ä¡ ÃʱâÈ­
        map[monster_y[i]][monster_x[i]] = '.';
        int direction = rand() % 4;

        switch (direction)
        {
        case 0: if (monster_y[i] > 0) monster_y[i]--; //À§
            break;
        case 1: if (monster_y[i] < SIZE - 1) monster_y[i]++; //¾Æ·¡
            break;
        case 2: if (monster_x[i] > 0) monster_x[i]--; //¿ÞÂÊ
            break;
        case 3: if (monster_x[i] < SIZE - 1) monster_x[i]++; //¿À¸¥ÂÊ
            break;
        }

        if (map[monster_y[i]][monster_x[i]] == '.') map[monster_y[i]][monster_x[i]] = 'M';
        else {
            monster_y[i] = prev_y;
            monster_x[i] = prev_x;
            map[prev_y][prev_x] = 'M';
        }
    }
}