单链表的增删查 逆置 倒数第k个节点等问题

对于单链表而言，它没有双链表那么复杂，它只有头节点，尾节点，节点数据，后继指针。在下面本人实现了 单链表的 增   删   插  查  改。

#include<stdio.h>
#include<assert.h>
#include<malloc.h>
#include<stdlib.h>
typedef int Datatype;
typedef struct SListNode
{
Datatype data;
struct SListNode*next;
}SListNode;
void PushBack(SListNode*&pHead, Datatype x);
void PopBack(SListNode *&pHead);
void PrintSlist(SListNode *&PHead);
void PushFrot(SListNode*&pHead,Datatype x);
void PopFront(SListNode*&pHead);
SListNode *Find(SListNode*pHead, Datatype x);
//void Insert(SListNode*pHead, Datatype pos, Datatype x);
void Insert(SListNode*pHead,  Datatype x);
void Erase(SListNode*&pHead,SListNode *pos );
void InsertNoNode(SListNode *pos, Datatype x);

SListNode* _BuyNode(Datatype x)
{
SListNode *temp = (SListNode*)malloc(sizeof(SListNode));
temp->data = x;
temp->next = NULL;
return temp;
}
void PushBack(SListNode*&pHead, Datatype x)
{
//1 空   2  不为空
if (pHead == NULL)
{
pHead = _BuyNode(x);
}
else
{
SListNode *tail = pHead;
while (tail->next != NULL)
{
tail = tail->next;
}
tail->next = _BuyNode(x);
}
}
void PopBack(SListNode *&pHead)
{
//1空  2 一个节点  3 多个节点
if(pHead == NULL)
{
return;
}
else if (pHead->next == NULL)
{
free(pHead);
pHead = NULL;
}
else{
SListNode *tail = pHead;
SListNode *tem = NULL;
while (tail->next != NULL)
{
tem = tail;
tail = tail->next;
}
free(tail);
tem->next = NULL;
}
}
void PrintSlist(SListNode *&PHead)  //打印链表
{
SListNode*cur = PHead;
while (cur!=NULL)
{
printf("%d->", cur->data);
cur = cur->next;
}
printf("NULL\n");
}
void PushFrot(SListNode*&pHead, Datatype x)   //头插
{
if (pHead == NULL)
{
pHead = _BuyNode(x);
}
else
{
SListNode *tmp = _BuyNode(x);
tmp->next = pHead;
pHead = tmp;
}
}
void PopFront(SListNode*&pHead)    //单链表头删
{
//1 空
//2 一个结点
//3 一个以上的节点
if (pHead == NULL)
{
return;
}
else if(pHead->next == NULL)
{
free(pHead);
pHead = NULL;
}
else
{
SListNode *tmp = pHead;
pHead = pHead->next;
free(tmp);
}

}

SListNode *Find(SListNode*pHead, Datatype x)    //查找节点
{
//assert(pHead);
SListNode *tail = NULL;//当前指针
Datatype tmp ;   //保存节点数据
if (pHead->data == x)
{
return pHead;
}
else
{
tail=pHead->next;
while (tail!= NULL)
{
tmp = tail->data;
if (tmp == x)  //把节点数据与要查找的数比较
{
return tail; //返回所要查找结点的地址
}
else
{
tail =tail->next;
}
}
printf("没有查到该数据！\n");
}
}

void Insert(SListNode*pos, Datatype x)  ////在指定节点  插入数据
{
assert(pos);
SListNode *tmp = _BuyNode(x);
tmp->next = pos->next;
pos->next = tmp;
}

void Erase(SListNode *&pHead,SListNode *pos) //删除指定位置的节点
{
assert(pos);
assert(pHead);
if (pHead == pos)
{
pHead = pHead->next;
free(pos);
return;
}
SListNode *prv = pHead;
while (prv)
{
if (prv->next == pos)
{
prv->next = pos->next;
free(pos);
break;
}
prv = prv->next;
}

}

//删除一个无头单链表
void DelNoNode(SListNode *pos)
{
assert(pos);
assert(pos->next);
SListNode *del = pos->next;
SListNode *next = del->next;
pos->data = del->data;
pos->next = next;
free(del);
}
//在无头单链表的一个非头节点前插入一个节点
void InsertNoNode(SListNode *pos, Datatype x)
{
assert(pos);
//assert(pos->next);
//1 种方法	//Datatype temp = 0;
//SListNode *behind = pos;
//SListNode*prv =_BuyNode(x);
//SListNode *next = behind->next;
//pos->next = prv;
//prv->next = next;
//temp = pos->data;
//pos->data = prv->data;
//prv->data = temp;
//2 种方法
SListNode*prv = _BuyNode(pos->data);
prv->next = pos->next;
pos->next = prv;
pos->data = x;
}
//查找中间节点
SListNode *FindmidNode(SListNode *phead)
{
SListNode *fast = phead;
SListNode *slow = phead;
while (fast&&fast->next)
{
fast = fast->next->next;
slow = slow->next;
}
return slow;
}

//找倒数第k个节点
SListNode *FindkNode(SListNode *phead, int k)
{
SListNode *fast = phead;
SListNode *slow = phead;
/*for (int i = 1; i<=k-1; i++)
{
fast = fast->next;
}
while (fast->next)
{

slow = slow->next;
fast = fast->next;
}*/
while (fast&&k--)
{

fast= fast->next;
if (fast == NULL)
return NULL;
}
while (fast)
{
slow = slow->next;
fast = fast->next;
}
return slow;
}
//从尾到头打印链表
void PrintTailToHead(SListNode*phead)
{
if (phead)
{
PrintTailToHead(phead->next);
printf("%d ", phead->data);
}
}
//
SListNode *Reverse(SListNode *phead)//单链表的逆置
{
SListNode *cur = phead;
SListNode *newhead = NULL;
while (cur)
{
SListNode*tmp =cur;
cur = cur->next;
tmp->next =newhead;
newhead = tmp;
}
return newhead;
}
void test1()
{
SListNode*list = NULL;
PushBack(list, 1);
PushBack(list, 3);
PushBack(list, 2);
PushBack(list, 4);
PushBack(list, 6);
PrintSlist(list);
}
void test2()
{
SListNode*list = NULL;
PushBack(list, 1);
PushBack(list, 2);
PushBack(list, 3);
PushBack(list, 4);
PushBack(list, 5);
PushBack(list, 6);
PushBack(list, 7);
PrintSlist(list);
//Find(list, 4);
//Insert(list,7, 8);
SListNode *pos = Find(list, 1);
Erase(list,pos );
PrintSlist(list);
}
void test3()
{
SListNode*list = NULL;
PushBack(list, 1);
PushBack(list, 2);
PushBack(list, 3);
PushBack(list, 4);
PushBack(list, 5);
PushBack(list, 6);
PushBack(list, 7);
PrintSlist(list);
SListNode *pos = Find(list ,7);
Insert(pos, 2);
PrintSlist(list);
}
void test4()
{
SListNode*list = NULL;
PushBack(list, 1);
PushBack(list, 2);
PushBack(list, 3);
PushBack(list, 4);
PushBack(list, 5);
PushBack(list, 6);
PushBack(list, 7);
PrintSlist(list);
/*SListNode *pos = list;
DelNoNode(pos);*/
SListNode *pos = Find(list,1);
InsertNoNode(pos, 9);
PrintSlist(list);
}
void test5()
{
SListNode *list = NULL;
PushBack(list, 1);
PushBack(list, 8);
PushBack(list, 2);
PushBack(list, 3);
PushBack(list, 4);
PushBack(list, 5);
PrintSlist(list);
//SListNode*pos = FindmidNode(list);
SListNode*pos =FindkNode(list, 5);
printf("%d\n", pos->data);
//PrintSlist(list);
}
void test6()
{
SListNode*list = NULL;
PushBack(list, 1);
PushBack(list, 3);
PushBack(list, 2);
PushBack(list, 4);
PushBack(list, 6);
//
SListNode*pos=Reverse(list);
PrintTailToHead(pos);
}
int main()
{
//test1();
test6();
system("pause");
return 0;
}