不带头结点的单链表c语言,数据结构：C语言实现----不带头结点单链表总结

不带头结点的单链表结构体声明

typedef struct Node

{

int data;

struct Node *next;

}Node, *LinkList;

(1)初始化

void InitLinkList(LinkList *plist) //plist为二级指针，主函数传递第一个结点指针的地址

{

assert(plist!=NULL);

if(plist == NULL)

return;

*plist = NULL;

}

(2)求链表长度

int ListLength(LinkList plist) //不需要修改链表，则只需传递一级指针

{

int count=0;

while(plist != NULL)

{

count++;

plist=plist->next;

}

return count;

}

(3)得到某个结点，函数返回该结点

LinkList GetNode(LinkList plist, int pos)

{

assert(plist!=NULL);

if(plist == NULL)

return NULL;

LinkList p=plist;

while(pos > 1) //pos为1即找到该位置，链表是从第一个结点算起

{

p=p->next;

pos--;

}

return p;

}

(4)静态函数：申请结点空间

static LinkList NodeApply(LinkList next, int val)

{

LinkList q=(Node *)malloc(sizeof(Node));

assert(q != NULL);

if (q == NULL)

return NULL;

q->data=val;

q->next=next;

return q;

}

(5)插入

void Insert(LinkList *plist, int pos, int val)

{

assert(plist!=NULL);

if(plist == NULL)

return;

if(pos < 0 || pos >ListLength(*plist))

return;

if(pos == 0) //头插要单独考虑

{

*plist=NodeApply(*plist,val); //即*plist指向新节点

return;

}

LinkList p=GetNode(*plist, pos); //要插入其后的结点的位置

p->next=NodeApply(p->next, val);

}

(6)头插

void InsertHead(LinkList *plist, int val)

{

assert(plist!=NULL);

if(plist == NULL)

return;

*plist=NodeApply(*plist,val);

}

(7)尾插

void InsertTail(LinkList *plist, int val)

{

assert(plist!=NULL);

if(plist == NULL)

return;

Insert(plist, ListLength(*plist), val);

}

(8)输出

void Show(LinkList plist)

{

for(Node *p=plist; p!=NULL; p=p->next)

{

printf("%d -->",p->data);

}

printf("NULLn");

}

(9)删除

void Delete(LinkList *plist, int pos)

{

assert(plist != NULL);

if(plist == NULL)

{

return;

}

if(pos<=0 || pos>ListLength(*plist))

{

return;

}

if(pos == 1) //头删特殊考虑

{

LinkList p=*plist;

*plist=p->next;

free(p);

return;

}

LinkList p=GetNode(*plist, pos-1); //要删除结点的前一个结点

LinkList q=p->next; //要删除的结点

p->next=q->next;

free(q);

}

(10)头删

void DeleteHead(LinkList *plist)

{

assert(plist != NULL);

if(plist == NULL)

{

return;

}

LinkList p=*plist;

*plist=p->next;

free(p);

}

(11)尾删

void DeleteTail(LinkList *plist)

{

assert(plist != NULL);

if(plist == NULL)

{

return;

}

Delete(plist,ListLength(*plist));

}

(12)判空

int ListEmpty(LinkList plist)

{

if(plist == NULL) //第一个结点指针指向空

return -1; //为空

return 0;

}

(13)链表清空

void ClearList(LinkList *plist)

{

assert(plist != NULL);

if(plist == NULL)

{

return;

}

while(!ListEmpty(*plist)) //只要不为空

{

DeleteHead(plist);//头删

}

}

主函数

int main()

{

LinkList plist; //栈区定义一个结点指针类型

InitLinkList(&plist);

Insert(&plist,0,10);

Insert(&plist,0,20);

Insert(&plist,0,30);

Insert(&plist,1,40);

InsertHead(&plist,50);

InsertTail(&plist,60);

Show(plist);

DeleteTail(&plist);

Show(plist);

ClearList(&plist);

Show(plist);

}