#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

typedef int SLDateType; //鏈表中存儲(chǔ)的數(shù)據(jù)類(lèi)型，可換成其他

typedef struct SListNode
{
	SLDateType date;
	struct SListNode* next; //指向下一個(gè)節(jié)點(diǎn)的指針
}SListNode;

SListNode* BuyListNode(SLDateType x)
{
    SListNode* newNode = (SListNode*)malloc(sizeof(SListNode));
    if (NULL == newNode)
    {
        printf("malloc error\n"); //內(nèi)存開(kāi)辟失敗
        exit(-1);
    }
    else
    {
        newNode->date = x; // 給新節(jié)點(diǎn)賦值
        newNode->next = NULL;
    }
    return newNode;
}

void SListPushFront(SListNode** pphead/*要改動(dòng)頭指針，所以要傳遞二級(jí)指針*/, SLDateType x)
{
    SListNode* newNode = BuyListNode(x); //申請(qǐng)節(jié)點(diǎn)
    newNode->next = *pphead;
    *pphead = newNode;
}

void SListPushBack(SListNode** pphead, SLDateType x)
{
    SListNode* newNode = BuyListNode(x);
    if (*pphead == NULL) //若頭指針為空，則鏈表為空鏈表，直接將新節(jié)點(diǎn)接到頭指針后
    {
        *pphead = newNode;
    }
    else
    {
        SListNode* tail = *pphead;
        while (tail->next != NULL) //找鏈表的尾部
        {
            tail = tail->next;
        }
        tail->next = newNode;//將新節(jié)點(diǎn)接到尾部
    }
}

void SListPopBack(SListNode** pphead)
{
	assert(pphead);

	if (*pphead == NULL)//鏈表為空，則不進(jìn)行任何操作
	{
		return;
	}
	else if ((*pphead)->next == NULL) //鏈表只有一個(gè)節(jié)點(diǎn)
	{
		free(*pphead);
		*pphead = NULL;
	}
	else//其余情況
	{
		SListNode* tail = *pphead; //鏈表的尾部節(jié)點(diǎn)
		SListNode* pre = NULL;//鏈表尾的前一個(gè)節(jié)點(diǎn)
		while (tail->next != NULL)//找尾
		{
			pre = tail;
			tail = tail->next;
		}
		pre->next = tail->next; //將尾節(jié)點(diǎn)的指針域賦值給前一個(gè)節(jié)點(diǎn)的指針域
		free(tail);
	}
}

void SListPopFront(SListNode** pphead)
{
    assert(pphead);
    if (*pphead == NULL) //鏈表為空什么也不做
    {
        return;
    }
    else
    {
        SListNode* head = *pphead;//記錄原本的第一個(gè)節(jié)點(diǎn)
        *pphead = head->next; //讓頭指針指向第二個(gè)節(jié)點(diǎn)
        free(head);//釋放第一個(gè)節(jié)點(diǎn)
    }
}

SListNode* SListFind(SListNode* phead, SLDateType x)
{
    SListNode* cur = phead;
    while (cur != NULL)
    {
        if (cur->date == x) //找到則返回該節(jié)點(diǎn)
        {
            return cur;
        }
        cur = cur->next;
    }
    return NULL; //未找到則返回空
}

void SListInsert(SListNode** pphead, SListNode* pos/*要插入的位置*/, SLDateType x)
{
	assert(pphead);
	assert(pos);

	if (*pphead == pos)
	{
		SListPushFront(pphead, x);
	}
	else
	{
		SListNode* cur = *pphead; //當(dāng)前所指向的位置
		SListNode* pre = NULL; //前一個(gè)節(jié)點(diǎn)
		while (cur != pos)
		{
			pre = cur;
			cur = cur->next;
		}
		SListNode* newNode = BuyListNode(x);
		pre->next = newNode;
		newNode->next = cur;
	}
}

void SListErase(SListNode** pphead, SListNode* pos/*要插入的位置*/)
{
	assert(pphead);
	assert(pos);

	if (*pphead == pos)
	{
		SListPopFront(pphead);
	}
	else
	{
		SListNode* cur = *pphead;
		SListNode* pre = *pphead;
		while (cur != pos)
		{
			pre = cur;
			cur = cur->next;
		}
		pre->next = cur->next;
		free(cur);
	}
}

void SListDestory(SListNode** pphead)
{
    if (*pphead == NULL)
    {
        return;
    }
    else
    {
        while (*pphead != NULL)
        {
            SListNode* cur = *pphead;
            *pphead = cur->next;
            free(cur);
        }
    }
}