C语言 ----- 链表算法实现

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

typedef struct Node
{
int data;
struct Node * pNext;
}NODE,*PNODE;

PNODE create_list(void);
void traverse_list(PNODE);
bool is_empty(PNODE pHead);

int length_list(PNODE);
bool insert_list(PNODE, int, int);
bool delete_list(PNODE, int, int*); //int * 删除的数据
void sort_list(PNODE);

int main(void)
{
PNODE pHead = NULL;
pHead = create_list();
traverse_list(pHead);
//is_empty(pHead);
//int len = length_list(pHead);
//printf("链表长度：%d\n",len);
//sort_list(pHead);
//traverse_list(pHead);
insert_list(pHead,3,222);
traverse_list(pHead);

int val;
if(delete_list(pHead,2,&val)){
printf("删除的结点是：%d\n",val);
}
else
{
printf("您删除的元素不存在!\n");
}
traverse_list(pHead);
return 0;
}

PNODE create_list(void)
{
int len;//有效节点个数
int i;
int val;//输入的值

PNODE pHead = (PNODE)malloc(sizeof(NODE));
if(NULL == pHead)
{
printf("分配失败，程序终止!\n");
exit(-1);
}
//尾结点
PNODE pTail = pHead;
pTail->pNext = NULL;

printf("请您输入需要生成的链表节点的个数：len = ");

scanf("%d",&len);

for(i=0; i<len; ++i)
{
printf("请输入第%d个节点的值: ",i+1);
scanf("%d",&val);

PNODE pNew = (PNODE)malloc(sizeof(NODE));
if(NULL == pNew)
{
printf("分配失败, 程序终止!\n");
exit(-1);
}

pNew->data = val;
pTail->pNext = pNew;
pNew->pNext = NULL;
pTail = pNew; //指向尾结点
}

return pHead;
}

void traverse_list(PNODE pHead)
{
PNODE p = pHead->pNext;
printf("遍历元素：");
while(NULL != p)
{
printf("%d ",p->data);
p = p->pNext;
}

printf("\n");
}

bool is_empty(PNODE pHead)
{
if(NULL == pHead->pNext)
{
printf("链表为空!\n");
return true;
}
else
{
printf("链表不为空!\n");
return false;
}
}

int length_list(PNODE pHead)
{
PNODE p = pHead->pNext;
int len = 0;

while(NULL != p)
{
len++;
p = p->pNext;
}
return len;
}

void sort_list(PNODE pHead)
{
int i,j,t;
int len = length_list(pHead);
PNODE p,q;

for(i=0, p=pHead->pNext; i<len-1; i++,p=p->pNext)
{
for(j=i+1,q=p->pNext; j<len; j++)//q=p->pNext下一个元素
{
if(p->data > q->data)
{
t = p->data;
p->data = q->data;
q->data = t;
}

}
}
}

bool insert_list(PNODE pHead, int pos, int val)
{
int i = 0;
PNODE p = pHead;

//拿到<pos-1 前一个
while(NULL!=p && i<pos-1)
{
p = p->pNext;
i++;
}

if(i>pos-1 || NULL==p)
{
return false;
}

PNODE pNew = (PNODE)malloc(sizeof(NODE));

if(NULL == pNew)
{
printf("动态分配内存失败!\n");
exit(-1);
}

pNew->data = val;
PNODE q = p->pNext;
p->pNext = pNew;
pNew->pNext = q;

return true;
}

bool delete_list(PNODE pHead, int pos, int* pVal)
{
int i = 0;
PNODE p = pHead;
PNODE q;
//拿到<pos-1 前一个，为了删除它后边的元素
while(NULL!=p->pNext && i<pos-1)
{
p = p->pNext;
i++;
}

//pos 可能为负值
if(i>pos-1 || NULL==p->pNext)
{
return false;
}

q = p->pNext;
*pVal = q->data;
p->pNext = q->pNext;
free(q);

return true;
}