单链表的基本操作！！！

//定义

typedef int DataType;

typedef Sstruct SListNode {
DataType data; 
struct ListNode *pNext; // 指向下一个结点 

} SListNode;

//开辟新结点
SListNode _GreateNewNode(DataType data)
{
SListNode*pNewNode = (SListNode*)malloc(sizeof(SListNode));
assert(pNewNode);
SListNode* pNode;
pNewNode->data = data;
pNewNode->pNext = NULL;

}

// 初始化 
void SListInit(SListNode **ppFirst)
{
*ppFirst = NULL;
}

// 尾部插入 

void SListPushBack(SListNode** ppFirst, DataType data)
{
SListNode*pNewNode = (SListNode*)malloc(sizeof(SListNode));
assert(pNewNode);
SListNode* pNode;
pNewNode->data = data;
pNewNode->pNext = NULL;
//特殊情况
if (*ppFirst == NULL){
*ppFirst = pNewNode;
return;
}
//正常情况
for (pNode = *ppFirst; pNode->pNext != NULL; pNode = pNode->pNext)
{
}
pNode->pNext = pNewNode;

}

// 头部插入 
void SListPushFront(SListNode **ppFirst, DataType data)
{
SListNode*pNewNode = _GreateNewNode(data);
pNewNode->pNext = *ppFirst;
*ppFirst = pNewNode;

}

// 尾部删除 

void SListPopBack(SListNode **ppFirst)
{
SListNode* pNode;
SListNode* pDel;
//特殊情况
assert(**ppFirst);
if (*ppFirst == NULL)
{
return;
}
if ((*ppFirst)->pNext == NULL)
{
free(ppFirst);
*ppFirst = NULL;
return;
}
//找倒数第二个
for (pNode = *ppFirst; pNode->pNext != NULL; pNode = pNode->pNext)
{
pDel = pNode->pNext;
pNode->pNext = NULL;
free(pDel);
}

}

// 头部删除 
void SListPopFront(SListNode **ppFirst)
{
if (*ppFirst == NULL)
{
printf("空的%s\n");
return;
}
SListNode*pOldFirst = *ppFirst;
**ppFirst = (*ppFirst)->pNext;
free(pOldFirst);
}

// 给定结点插入，插入到结点前 

void SListInsert(SListNode **ppFirst, SListNode *pPos, DataType data)
{
SListNode*pNewNode = _GreateNewNode(data);
SListNode*pNode;
pNode->pNext = pPos;
for (pNode = *ppFirst; pNode->pNext != pPos; pNode = pNode->pNext)
{
pNode->pNext = pNewNode;
pNewNode->pNext = pPos;
}

}

// 给定结点删除 
void SListErase(SListNode **ppFirst, SListNode *pPos)
{
SListNode*pNode;
SListNode*pDel;
//如果pos就是第一个
if (*ppFirst == pPos)
{
SListPopFront(ppFirst);
return;
}
for (pNode = *ppFirst; pNode->pNext != pPos; pNode = pNode->pNext)
{
pDel = pNode->Next;
pNode->pNext = pPos->pNext;
free(pDel);
}

} 

// 按值查找，返回第一个找到的结点指针，如果没找到，返回 NULL 
int SListFind(SListNode *pFirst, DataType data)
{
SListNode*pNode; 
if (pNode == NULL)
{
printf("没找到%s\n");
return;
}
for (pNode = pFirst; pNode != NULL; pNode = pNode->pNext)
{
if (pNode->data == data)
{
return data;
}
}

}


// 按值删除，只删遇到的第一个 
void SListRemove(SListNode **ppFirst, DataType data)
{
SListNode*pPos = SListFind(*ppFirst, data);
if (pPos != NULL)
{
SListErase(ppFirst, pPos);
}

}

【1、遍历的起始条件，结果条件  pNode[第一个，最后一个]；

【2、如果发现data是要删除的，就不进行pNode->pNext=pCmp->pNext,不是就正常往后走；

【3、最后判断第一个是否为data

// 按值删除，删除所有的 
void SListRemoveAll(SListNode **ppFirst, DataType data)
{
SListNode*pPos;
#if 0
while ((pPos = SListFind(*ppFirst, data) != NULL))
{
SListErase(ppFirst, pPos);
}
#endif
SListNode*pNode = *ppFirst;
SListNode*pCmp;
while (pNode->pNext != NULL)
{
pCmp = pNode->pNext;
if (pCmp->data == data)
{
pNode->pNext = pCmp->pNext;
free(pCmp);
}
else{
pNode = pNode->pNext;
}
}
if ((**ppFirst)->data == data)
{
pNode = *ppFirst;
*ppFirst = (*ppFirst)->pNext;
free(pNode);
}

}

// 销毁 
void SListDestroy(SListNode **ppFirst)
{
SListNode* pNode;
for (pNode = *ppFirst; pNode->pNext != NULL; pNode = pNode->pNext)
*ppFirst = NULL;
}