剑指offer| |从尾到头打印链表

有三种方法：

第一种：采用设置一个标志结点的的方法。

先将标志放在NULL,遍历链表如果cur->next==flag,那么就将cur->data打印出来，然后将标志前移，再次遍历就可以打印倒数第二个数据，然后再将标志前移，知道标志，在头结点plist位置

第二种：采用递归将其打印出来

但三种：采用栈的思想。

因为栈是先进后出，这刚好与这道题的思想一样，最先的最后打印，那么就可以用栈来进行编写了

代码如下：

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

typedef int DataType;

typedef struct Linklist
{
	DataType data;
	struct Linklist* next;
}Node, *pNode, List, *pList;

void Init(pList* pplist)
{
	assert(pplist != NULL);
	*pplist = NULL;
}

pNode BuyNode(DataType d)
{
	pNode newNode = NULL;
	newNode = (pNode)malloc(sizeof(Node));
	newNode->data = d;
	newNode->next = NULL;
	return newNode;
}

void PushFront(pList* pplist, DataType d)
{
	pNode newNode = NULL;
	assert(pplist != NULL);
	newNode = BuyNode(d);
	newNode->next = *pplist;
	*pplist = newNode;
}

void Print(pList plist)
{
	if (plist == NULL)
	{
		return;
	}
	else
	{
		while (plist != NULL)
		{
			printf("%d-->", plist->data);
			plist = plist->next;
		}
	}
	printf("over\n");
}

//采用栈的方法打印
void PrintTailToHeadStack(pList plist)
{
	int stack[100] = { 0 };
	int top = 0;
	int i = 0;
	pNode cur = plist;
	while (cur != NULL)
	{
		stack[top++] = cur->data;
		cur = cur->next;
	}
	top--;
	while (top >= 0)
	{
		printf("%d-->", stack[top--]);
	}
	printf("over\n");
}

//采用递归的方法打印
void PtintTailToHeadRecursion(pList plist)
{
	if (plist == NULL)
	{
		return;
	}
	else
	{
		PtintTailToHeadRecursion(plist->next);
	}
	printf("%d\n", plist->data);
}

//采用标志的方法打印
void PrintTailToHead(pList plist)
{
	pNode flag = NULL;
	while (flag != plist)
	{
		pNode cur = plist;
		while (cur->next != flag)
		{
			cur = cur->next;
		}
		printf("%d-->", cur->data);
		flag = cur;
	}
	printf("over\n");
}

void Test()
{
	pList plist = NULL;
	Init(&plist);
	PushFront(&plist, 1);
	PushFront(&plist, 2);
	PushFront(&plist, 3);
	PushFront(&plist, 4);
	PrintTailToHead(plist);
	PtintTailToHeadRecursion(plist);
	PrintTailToHeadStack(plist);
	Print(plist);
}


int main()
{
	Test();
	return 0;
}