C语言 超详细介绍与实现线性表中的无头单向非循环链表

SLTnode* BuySListNode(SLDataType x)
{
	SLTNode* newnode = malloc(sizeof(SLTNode));
	if (newnode == NULL)
	{
		printf("malloc fail\n");
		exit(-1);
	}
	newnode->data = x;
	newnode->next = NULL;
	return newnode;
}

void SListPrint(SLTNode* phead)
{
	SLTNode* cur = phead;
	while (cur)
	{
		printf("%d->", cur->data);
		cur = cur->next;
	}
	printf("NULL\n");
}

void SListPushBack(SLTNode** pphead, SLDataType x)
{
	if (*pphead==NULL)
	{
		*pphead = BuySListNode(x);
		return;
	}
	else
	{
		SLTNode* tail;
		tail = *pphead;
		while (tail->next)
		{
			tail = tail->next;
		}
		tail->next = BuySListNode(x);
		return;
	}
}

void SListPushFront(SLTNode** pphead, SLDataType x)
{
	SLTNode* newnode = BuySListNode(x);
	newnode->next = *pphead;
	*pphead = newnode;
}

void SListPopBack(SLTNode** pphead)
{
	if (*pphead == NULL)
	{
		return;
	}
	else if((*pphead)->next==NULL)
	{
		*pphead = NULL;
	}
	else
	{
		SLTNode* prev = NULL;
		SLTNode* tail = *pphead;
		while (tail->next)
		{
			prev = tail;
			tail = tail->next;
		}
		free(tail);
		prev->next = NULL;
	}
}

void SListPopFront(SLTNode** pphead)
{
	if (*pphead == NULL)
	{
		return;
	}
	else
	{
		SLTNode* temp = *pphead;
		(*pphead) = (*pphead)->next;
		free(temp);
	}
}

SLTNode* SListSearch(SLTNode* phead, SLDataType x)
{
	while (phead)
	{
		if (phead->data == x)
		{
			return phead;
		}
		phead = phead->next;
	}
	return NULL;
}

void SListInsert(SLTNode** pphead, SLTNode* pos, SLDataType x)
{
	SLTNode* newnode = BuySListNode(x);
	if (*pphead == NULL)
	{
		return;
	}
	else if(*pphead==pos)
	{
		newnode->next = pos;
		*pphead = newnode;
	}
	else
	{
		SLTNode* cur = *pphead;
		while (cur->next != pos)
		{
			cur = cur->next;
		}
		newnode->next = pos;
		cur->next = newnode;
	}
}

void SListErase(SLTNode** phead, SLTNode* pos)
{
	if (*phead == NULL)
	{
		return;
	}
	else if (*phead == pos)
	{
		*phead == NULL;
	}
	else
	{
		SLTNode* cur = *phead;
		while (cur->next != pos)
		{
			cur = cur->next;
		}
		cur->next = pos->next;
		free(pos);
	}
}

typedef struct ListNode ListNode;
struct ListNode* removeElements(struct ListNode* head, int val)
{
    ListNode* cur=head;
    ListNode* prev=NULL;
    while(cur)
    {
        if(cur->val==val)
        {
            if(cur==head)
            {
                head=cur->next;
                free(cur);
                cur=head;
            }
            else
            {
                 prev->next=cur->next;
                 cur=cur->next;
            }
        }
        else
        {
            prev=cur;
            cur=cur->next;
        }
    }
    return head;
}

typedef struct ListNode ListNode; 
struct ListNode* reverseList(struct ListNode* head)
{
    ListNode* newhead=NULL;
    ListNode* cur=head;
    if(cur==NULL)
    {
        return cur;
    }
    ListNode* next=cur->next;
    while(cur)
    {
        cur->next=newhead;
        newhead=cur;
        cur=next;
        if(next)
        next=next->next;
    }
    return newhead;
}

struct ListNode* reverseList(struct ListNode* head)
{
    struct ListNode* cur = head;
    struct ListNode* newhead = NULL;
    while(cur)
    {
       struct ListNode* next = cur->next;
        cur->next = newhead;
        newhead = cur;
        cur = next; 
    }
    return newhead;
}