单向链表

 单向链表C++

class IntSLLNode
{
public:
	IntSLLNode()
	{
		next = 0;
	}
	IntSLLNode(int i, IntSLLNode *in = 0)
	{
		info = i;
		next = in;
	}
	int info;
	IntSLLNode *next;
private:
};

class IntSLList
{
public:
	IntSLList()
	{
		head = tail = 0;
	}

	~IntSLList();
	int isEmpty()
	{
		return head == 0;
	}

	void addToHead(int);
	void addToTail(int);
	int deleteFromHead();
	int deleteFromTail();
	void deleteNode(int);
	bool isInList(int)const;

private:
	IntSLLNode *head, *tail;
};

IntSLList::~IntSLList()
{
	for (IntSLLNode *p; isEmpty();)
	{
		p = head->next;
		delete head;
		head = p;
	}
}

void IntSLList::addToHead(int el)
{
	head = new IntSLLNode(el, head);
	if (tail == 0)
		tail = head;
}

void IntSLList::addToTail(int el)
{
	if (tail != 0)
	{
		tail->next = new IntSLLNode(el);
		tail = tail->next;
	}
	else
		head = tail = new IntSLLNode(el);
}

int IntSLList::deleteFromHead()
{
	int el = head->info;
	IntSLLNode *temp = head;
	if (head == tail)
	{
		head = tail = 0;
	}
	else
	{
		head = head->next;
	}
	delete temp;
	return el;
}

int IntSLList::deleteFromTail()
{
	int el = tail->info;
	if (head == tail) 
	{
		delete head;
		head = tail = 0;
	}
	else
	{
		IntSLLNode *temp;
		for (temp = head; temp->next != tail; temp = temp->next)
			delete temp;
		tail = temp;
		tail->next = 0;
	}
	return el;
}
void  IntSLList::deleteNode(int el)
{
	if (head != 0)
		if (head == tail && el == head->info)
		{
			delete head;
			head = tail = 0;
		}
		else if (el==head->info)
		{
			IntSLLNode *temp = head;
			head = head->next;
			delete temp;
		}
		else
		{
			IntSLLNode *temp, *pred;
			for (pred = head, temp = head->next; temp != 0 && !(temp->info == el); pred = pred->next, temp = temp->next);
			if (temp != 0)
			{
				pred->next = temp->next;
				if (temp->next)
					tail = pred;
				delete temp;
			}
		}
}

bool IntSLList::isInList(int el)const
{
	IntSLLNode *temp;
	for (temp = head; temp != 0 && !(temp->info = el); temp = temp->next)
		return temp != 0;
}