c实现无头结点单链表

头文件

#ifndef __LINKLIST_H__
#define __LINKLIST_H__

#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <malloc.h>

typedef int DataType;

typedef struct Node
{
DataType _data;
struct Node* _next;
}Node,*pNode,*pList;

void InitLinkList(pList* pplist);//初始化
void DestroyList(pList* pplist);//销毁单链表
void Display(pList plist);//遍历单链表

void PushBack(pList* pplist, DataType x);//尾插
void PopBack(pList* pplist);//尾删

void PushFront(pList* pplist, DataType x);//头插
void PopFront(pList* pplist);//头删

pNode Find(pList plist, DataType x);//查找元素的位置

void Insert(pList* pplist, pNode pos, DataType x);//指定位置插入
void Erase(pList* pplist, pNode pos);//指定位置删除

void Remove(pList* pplist, DataType x);//删除指定的元素
void RemoveAll(pList* pplist, DataType x);//删除指定元素的所有

void Sort(pList* pplist);//单向链表的排序
#endif

程序实现文件

#include "linklist.h"

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

void DestroyList(pList* pplist)
{
pNode cur = NULL;
pNode del = NULL;
assert(pplist);
cur = *pplist;
while(cur)
{
del = cur;
cur = cur->_next;
free(del);
}
free(cur);
*pplist = NULL;
}

void PushBack(pList* pplist, DataType x)
{
pNode cur = NULL;
pNode newnode = NULL;
assert(pplist);
cur = *pplist;
newnode = (pNode)malloc(sizeof(Node));
newnode->_data = x;
newnode->_next = NULL;
if(*pplist == NULL)
{
*pplist = newnode;
return;
}
while(cur->_next)
{
cur = cur->_next;
}
cur->_next = newnode;
}

void PopBack(pList* pplist)
{
pNode cur = NULL;
assert(pplist);
cur = *pplist;
if(*pplist == NULL)
{
return;
}
if(cur->_next == NULL)
{
free(cur);
*pplist = NULL;
return;
}
while(cur->_next->_next)
{
cur = cur->_next;
}
free(cur->_next);
cur->_next = NULL;
}

void PushFront(pList* pplist, DataType x)
{
pNode cur = NULL;
pNode newnode = NULL;
assert(pplist);
cur = *pplist;
newnode = (pNode)malloc(sizeof(Node));
newnode->_data = x;
newnode->_next = NULL;
if(*pplist == NULL)
{
*pplist = newnode;
return;
}
else
{
newnode->_next = cur;
*pplist = newnode;
}

}

void PopFront(pList* pplist)
{
pNode cur = NULL;
pNode del = NULL;
assert(pplist);
cur = *pplist;
if(*pplist == NULL)
{
return;
}
if(cur->_next == NULL)
{
free(cur);
*pplist = NULL;
return;
}
del = cur;
cur = cur->_next;
free(del);
*pplist = cur;
}

pNode Find(pList plist, DataType x)
{
pNode pos = plist;
while(pos)
{
if(pos->_data == x)
{
return pos;
}
pos = pos->_next;
}
return NULL;
}

void Insert(pList* pplist, pNode pos, DataType x)
{
pNode cur = NULL;
pNode newnode = NULL;
assert(pplist);
cur = *pplist;
newnode = (pNode)malloc(sizeof(Node));
newnode->_data = x;
newnode->_next = NULL;
if(*pplist == NULL)
{
*pplist = newnode;
return;
}
while(cur->_next != pos)
{
cur = cur->_next;
}
newnode->_next = pos;
cur->_next = newnode;
}

void Erase(pList* pplist, pNode pos)
{
pNode cur = NULL;
assert(pplist);
cur = *pplist;
if(*pplist == NULL)
{
return;
}
if((pos == *pplist)&&pos->_next)
{
*pplist = pos->_next;
free(pos);
return;
}
while((cur->_next != pos)&&cur)
{
cur = cur->_next;
}
cur->_next = pos->_next ;
free(pos);
}

void Remove(pList* pplist, DataType x)
{
pNode pos = NULL;
assert(pplist);
pos = Find(*pplist,x);
Erase(pplist, pos);

}

void RemoveAll(pList* pplist, DataType x)
{
pNode cur = NULL;
pNode dec = NULL;
assert(pplist);
cur = *pplist;
while(cur)
{
if(cur->_data == x)
{
pNode del = cur;
if(cur == *pplist)
{
*pplist = cur->_next;
}
else
{
dec->_next = cur->_next;
}
cur = cur->_next;
free(del);
}
else
{
dec = cur;
cur = cur->_next;
}
}
}

void Sort(pList* pplist)
{
pNode cur = NULL;
pNode dec = NULL;
assert(pplist);
cur = *pplist;
for(; cur; cur = cur->_next)
{
for(dec = cur->_next; dec; dec = dec->_next)
{
if(cur->_data > dec->_data)
{
DataType tmp;
tmp = cur->_data;
cur->_data = dec->_data;
dec->_data = tmp;
}
}
}
}

void Display(pList plist)
{
pNode cur = plist;
while(cur)
{
printf("%d->",cur->_data);
cur = cur->_next;
}
printf("NULL\n");
}

测试文件

#include "linklist.h"

void test()
{
pNode plist;
InitLinkList(&plist);
PushBack(&plist, 1);
PushBack(&plist, 2);
PushBack(&plist, 3);
PushBack(&plist, 4);
Display(plist);//尾插输入1234
PopBack(&plist);
Display(plist);//尾删一个
PopBack(&plist);
Display(plist);//尾删一个
PopBack(&plist);
Display(plist);//尾删一个
PopBack(&plist);
Display(plist);//尾删一个
PopBack(&plist);
Display(plist);//尾删一个
DestroyList(&plist);
Display(plist);
}

void test1()
{
pNode plist;
InitLinkList(&plist);
PushFront(&plist, 1);
PushFront(&plist, 2);
PushFront(&plist, 3);
PushFront(&plist, 4);
Display(plist);//头插输入1234
PopFront(&plist);
Display(plist);//头删一个
PopFront(&plist);
Display(plist);//头删一个
PopFront(&plist);
Display(plist);//头删一个
PopFront(&plist);
Display(plist);//头删一个
PopFront(&plist);
Display(plist);//头删一个
DestroyList(&plist);
Display(plist);
}

void test2()
{
pNode plist;
pNode pos = NULL;
InitLinkList(&plist);
PushFront(&plist, 1);
PushFront(&plist, 2);
PushFront(&plist, 3);
PushFront(&plist, 4);
Display(plist);
pos = Find(plist, 3);//找到3的位置
printf("%d\n",pos->_data);
Insert(&plist, pos, 5);//在3元素的位置处插入元素5
Display(plist);
Erase(&plist, pos);//删除3元素位置处的元素
Display(plist);
Remove(&plist, 5);//删除元素5
Display(plist);
DestroyList(&plist);
Display(plist);
}

void test3()
{
pNode plist;
InitLinkList(&plist);
PushFront(&plist, 3);
PushFront(&plist, 1);
PushFront(&plist, 3);
PushFront(&plist, 2);
PushFront(&plist, 3);
PushFront(&plist, 4);
PushFront(&plist, 3);
Display(plist);
RemoveAll(&plist, 3);//删除指定的所有相同的元素
Display(plist);
DestroyList(&plist);
Display(plist);
}

void test4()
{
pNode plist;
InitLinkList(&plist);
PushFront(&plist, 2);
PushFront(&plist, 1);
PushFront(&plist, 6);
PushFront(&plist, 4);
PushFront(&plist, 5);
PushFront(&plist, 9);
PushFront(&plist, 4);
Display(plist);
Sort(&plist);//排序单链表
Display(plist);
DestroyList(&plist);
Display(plist);
}

int main()
{
test();
test1();
test2();
test3();
test4();
return 0;
}

所有程序实现图