链表插入新节点的实现

链表插入节点的简单实现

-函数设计：void insertLinkList(struct LinkNode *pHeader, int oldVal, int newVal);
-函数功能：在链表中查询旧值，查到后在该位置前插新节点。

若查不到，则在尾节点位置后插新节点。

• 查询旧值，查找到所在节点

为了更好实现链表的插入，创建两个临时节点指针：当前节点指针pCurrent，前驱节点指针pPrevious

//创建两个临时的节点
struct LinkNode *pCurrent = pHeader->next;//当前节点
struct LinkNode *pPrevious = pHeader;//当前节点的前去节点

while(pCurrent != NULL)
{
	if(pCurrent->data == oldVal)
		break;
	pPrevious = ppCurrent;
	ppCurrent = ppCurrent->next;
}

• 创建新的节点，与当前节点和前驱节点建立关系，插入链表中去

//创建新的节点并初始化
struct LinkNode *pNewNode = malloc(sizeof(struct LinkNode));
pNewNode->data = newVal;
pNewNode->next = NULL;

pNewNode->next = pCurrent;
pPrevious->next = pNewNode;

• InsertLinkList()函数的最终实现

若pCurrent == NULL，则对链表进行尾插，若pCurrent != NULL则对所在节点进行前插

void insertLinkList(struct LinkNode *pHeader,int oldVal,init newVal)
{
	if(pHeader == NULL)
		return;
	//创建两个临时节点指针：当前节点指针、前驱节点指针
	struct LinkNode *pCurrent = pHeader->next;
	struct LinkNode *pPrevious = pHeader;

	while(pCurrent != NULL)
	{
		if(pCurrent->data == oldVal)
			break;
		pPrevious = pCurrent;
		pCurrent = pCurrent->next;
	}
	
	struct LinkNode *pNewNode = malloc(sizeof(struct LinkNode));
	pNewNode->data = oldVal;
	pNewNode->next = NULL;

	PNewNode->next = pCurrent;
	pPrevious->next = pNewNode;
}