线性表——单链表

定义结构体

结构体成员包括：结点保存的数据和下一个结点的结构体指针

typedef int SLTDataType;
typedef struct SingleList
{
	SLTDataType data;
	struct SingleList* next;
}SLT;

函数实现

链表打印

void SLTprint(SLT* phead)
{
	assert(phead);
	while (phead != NULL)
	{
		printf("%d->", phead->data);
		phead = phead->next;
	}
	printf("NULL\n");
}

链表结点的创建和赋值

SLT* SLTMemCrt(SLTDataType x)
{
	SLT* new = (SLT*)malloc(sizeof(SLT));
	if (NULL == new)
	{
		perror("malloc fail");
		return NULL;
	}
	new->data = x;
	return new;
}

链表的头插

void SLTpushfront(SLT** pphead, SLTDataType x)
{
	assert(pphead);
	SLT* new = SLTMemCrt(x);
	new->next = *pphead;
	*pphead = new;
}

链表的头删

void SLTpopfront(SLT** pphead) 
{
	assert(pphead);
	assert(*pphead);
	SLT* tmp = (*pphead)->next;
	free(*pphead);
	*pphead = tmp;
}

链表的尾插(链表尾插效率低，一般不用)

void SLTpushback(SLT** pphead, SLTDataType x)
{
	assert(pphead);
	SLT* new = SLTMemCrt(x);
	SLT* cur = *pphead;
	if (cur == NULL)
	{
		*pphead = new;
	}
	else 
	{
		while (cur->next != NULL)
		{
			cur = cur->next;
		}
		cur->next = new;
	}
	new->next = NULL;
}

链表的尾删(效率低，一般不用)

void SLTpopback(SLT** pphead)
{
	assert(pphead);
	assert(*pphead);
	SLT* cur = *pphead;
	if (cur->next == NULL) 
	{
		free(cur);
		*pphead = NULL;
	}
	else 
	{
		while (cur->next->next != NULL)
		{
			cur = cur->next;
		}
		free(cur->next);
		cur->next = NULL;
	}
}

链表数据查找，返回结点指针

SLT* SLTFind(SLT* phead, SLTDataType x)
{
	if (phead == NULL)    //链表为空
		return NULL;
	while (phead->next != NULL)
	{
		if (phead->data == x)
			return phead;
		else
			phead = phead->next;
	}
	printf("not found\n");
	return NULL;
}

链表某数据后插入

void SLTInsertAfter(SLT** pphead, SLTDataType fdata, SLTDataType x)
{
	//fdata表示要插入x的前一个位置的值
	assert(pphead);
	SLT* des = SLTFind(*pphead, fdata);
	SLT* new = SLTMemCrt(x);
	if(des == NULL)
	{ 
		printf("insert fail\n");
		return;
	}
	else  
	{
		new->next = des->next;
		des->next = new;
	}
}

链表某数据前插入

void SLTInsertFront(SLT** pphead, SLTDataType fdata, SLTDataType x)
{
	//fdata表示要插入x的后一个位置的值
	assert(pphead);
	SLT* des = SLTFind(*pphead, fdata);
	SLT* new = SLTMemCrt(x);
	//遍历找到des的前一个结点的指针，效率低
	//这里在des后插入一个结点，将值互换也可达到目的
	if (des == NULL)
	{
		printf("insert fail\n");
		return;
	}
	else
	{
		//值交换
		new->data = des->data;
		des->data = x;
		//后插入结点
		new->next = des->next;
		des->next = new;
	}
}

链表某数据后删除

void SLTEraseAfter(SLT** pphead, SLTDataType fdata)
{
	assert(pphead);
	assert(*pphead);
	SLT* des = SLTFind(*pphead, fdata);
	if (des == NULL || des->next == NULL)
	{
		printf("erase fail\n");
	}
	SLT* del = des->next;
	des->next = del->next;
	free(del);
}

链表某数据前删除

void SLTEraseFront(SLT** pphead, SLTDataType fdata)
{
	assert(pphead);
	assert(*pphead);
	SLT* des = SLTFind(*pphead, fdata);
	if (des == NULL || des == *pphead)
	{
		printf("erase fail\n");
		return;
	}
	SLT* cur = *pphead;
	if (cur->next == NULL)
	{
		free(cur);
		*pphead == NULL;
		return;
	}
	while (cur->next->next != des)
	{
		cur = cur->next;
	}
	free(cur->next);
	cur->next = des;
}

链表全释放

void SLTDestory(SLT** pphead)
{
	assert(pphead);
	SLT* cur = *pphead;
	if (cur == NULL)
		return;
	do
	{
		SLT* tmp = cur->next;
		free(cur);
		cur = tmp;
	} while (cur != NULL);
	*pphead = NULL;
}