数组环、链表环、约瑟夫环

双向循环链表

struct node
{
  int id;
  int data;
  int status;
  struct node *up;
  struct node *next;
};

class DoubleLink
{
public:
  DoubleLink();
  ~DoubleLink();

  node* up();
  node* next();
  node* getCurrent();
  int   getSize();

  node* addNode(int size);
  void  deleteNode(int size); //  删除size个节点
  void  deleteLink();         //  删除整条

  void  show();
  void  showDesc();

private:
  node* current;
  void  creatLink();

};

DoubleLink::DoubleLink()
{
  creatLink();
}

DoubleLink::~DoubleLink()
{
  if (current != NULL)
    deleteLink();
}

void DoubleLink::creatLink()
{
  current = (node *)malloc(sizeof(node));

  current->up = current;
  current->next = current;
  current->id = 0;
  current->data = 0;
  current->status = 0;
}

void DoubleLink::deleteLink()
{
  current->up->next = NULL;
  while (current != NULL)
  {
    node *p = current->next;
    free(current);
    current = p;
  }
  current = NULL;
}

void DoubleLink::deleteNode(int size)
{
  if (getSize() <= size) deleteLink();
  node *beg = current->up;

  for (int i = 0; i < size; i++)
  {
    node *p = current->next;
    free(current);
    current = p;
  }

  current->up = beg;
  beg->next = current;
}

node* DoubleLink::addNode(int size)
{
  node *beg = current;
  node *end = current->next;

  for (int i = 0; i < size; i++)
  {
    node *mid = (node *)malloc(sizeof(node));
    beg->next = mid;
    mid->up = beg;
    beg = mid;
  }

  beg->next = end;
  end->up   = beg;

  return current;
}

int DoubleLink::getSize()
{
  int size = 1;
  node *p = current->next;

  while (p != current)
  {
    p = p->next;
    size++;
  }
  return size;
}

void DoubleLink::show()
{
  cout << "DoubleLink Show :" << endl;
  cout << "第0个: " << current->data << endl;

  node *p = current;
  p = p->next;

  for (int i = 1; p != current; i++)
  {
    cout << "第"<< i << "个: " << p->data << endl;
    p = p->next;
  }
}

void DoubleLink::showDesc()
{
  cout << "DoubleLink Show Desc :" << endl;
  cout << "第0个: " << current->data << endl;

  node *p = current;
  p = p->up;

  for (int i = 1; p != current; i++)
  {
    cout << "第"<< i << "个: " << p->data << endl;
    p = p->up;
  }
}


node* DoubleLink::up()
{
  return current->up;
}
node* DoubleLink::getCurrent()
{
  return current;
}
node* DoubleLink::next()
{
  return current->next;
}