单链表、双链表、循环链表总结

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

typedef struct NODE
{
struct NODE *link;
int 	value;

} Node;//最好放在头文件中

Node 	*sll_creat();
int 	sll_length(Node *p);
Node 	*sll_del(Node *head,int value);
void 	sll_print(Node *head);
Node 	*sll_insert(Node *head,int n);
Node 	*sll_reverse(Node *head);

int main()
{
Node *p;
p=sll_creat();
sll_print(p);
p=sll_del(p,3);
sll_print(p);
p=sll_insert(p,4);
sll_print(p);
p=sll_reverse(p);
sll_print(p);
return 0;
}

Node *sll_creat()
{
int data;
Node *p;
Node *head;
Node *new;
Node *temp;//用来删除没用的head
head=(Node *)malloc(sizeof(Node));
p=head;//head没有改变， 改变的是p， head用来返回
printf("please input the values,end with EOF:\n");
while(scanf("%d",&data)==1)
{
new=(Node *)malloc(sizeof(Node));
if(new==NULL)
{
printf("malloc error!\n");
return NULL;
}
new->value=data;
p->link=new;
p=new;
}
temp=head;
head=head->link;//将第一个无用节点head去除,如何free掉?
p->link=NULL;
free(temp);//删除没用的head，防止内存泄露
return head;
}

int sll_length(Node *p)
{
int count=0;
while(p->link!=NULL)
{
count++;
p=p->link;
}
count++;//由于尾节点的存在
return count;

}
void sll_print(Node *head)
{
int n;
Node *p=head;
n=sll_length(p);
printf("there are %d records,they are:\n",n);
while(p->link!=NULL)
{
printf("%d\n",p->value);
p=p->link;
}
printf("%d\n",p->value);
}
/*
*1.此函数缺点是只能删除第一个value出现的节点
*2.此函数验证了在结构体中的value跟局部变量value不冲突
*/
Node *sll_del(Node *head,int value)//缺点，只能删除第一个value所在的节点
{
Node *p1,*p2;
p1=head;
while(value!=p1->value&&p1->link!=NULL)//遍历链表，找到需要删除的节点
{
p2=p1;
p1=p1->link;
}
if(value==p1->value)
{
if(p1==head)//单独处理头节点
{
head=p1->link;
free(p1);
}
else
{
p2->link=p1->link;
free(p1);
}
}
else
{
if(p1->value==value)//单独处理尾节点
{
p2->link=NULL;
free(p1);
}
else
printf("can't find the value:%d",value);
}
return head;

}
/*
*此函数是在节点中的数字递增的前提下才起作用（即该链表要为有序链表，value按升序排列）
*
*/
Node *sll_insert(Node *head,int n)
{
Node *p=head;
Node *p_prev;
Node *p0=(Node *)malloc(sizeof(Node));
while(n>=p->value&&p->link!=NULL)
{
p_prev=p;
p=p->link;
}
if(p->value>n)
{
if(p==head)
{
p0->value=n;
p0->link=head;
head=p0;

}
else
{
p0->value=n;
p_prev->link=p0;
p0->link=p;
}
}
else
{
p0->value=n;
p->link=p0;
p0->link=NULL;
}
return head;
}

Node *sll_reverse(Node *head)
{
Node *p1;
Node *p2;
Node *p3;
p1=head;p2=p1->link;
if(p1==NULL)
{
return head;
}
else if(p1->link==NULL)
{
head=p1->link;
head->link=p1;
p1->link=NULL;
}
else
{
while(p2->link)
{
p3=p2->link;
p2->link=p1;
p1=p2;
p2=p3;
}
}
p2->link=p1;
head->link=NULL;
head=p2;
return head;
}

#include <stdio.h>
#include <malloc.h>
typedef struct NODE
{
struct NODE	*next;
struct NODE	*prev;
int	value;
} Node;//不要忘了分号
Node	*dll_creat();
void	dll_print(Node *head);
int 	dll_length(Node *head);
Node	*dll_del(Node *head,int value);
Node *dll_insert(Node *head,int n);
int main()
{
Node *p=dll_creat();
dll_print(p);
p=dll_del(p,5);
dll_print(p);
p=dll_insert(p,6);
dll_print(p);
return 0;
}
Node *dll_creat()
{
Node *head;
Node *p;
Node *temp;
Node *new;
int value;
printf("please input the values,end with eof:\n");
head=(Node *)malloc(sizeof(Node));
if(head==NULL)
{
printf("malloc error!!!\n");
return NULL;
}
p=head;
while(scanf("%d",&value)==1)
{
new=(Node *)malloc(sizeof(Node));
if(new==NULL)
{
printf("malloc error!!!\n");
return NULL;
}
new->value=value;
p->next=new;
new->prev=p;
p=new;
}
temp=head;
head=head->next;
head->prev=NULL;
p->next=NULL;
free(temp);
return head;
}
int 	dll_length(Node *head)
{
Node *p;
int length=0;
p=head;
while(p->next!=NULL)
{
p=p->next;
length++;
}
length++;
return length;
}
void	dll_print(Node *head)
{
int n=dll_length(head);
Node *p=head;
printf("there are %d records,they are :\n",dll_length(p));
while(p->next!=NULL)
{
printf("%d\n",p->value);
p=p->next;

}
printf("%d\n",p->value);
}
Node 	*dll_del(Node *head,int value)
{
Node *p=head;
while(p->value!=value&&p->next!=NULL)
{
p=p->next;
}
if(p->next==NULL)//尾节点
{
if(p->value==value)
{
p->prev->next=NULL;
p->prev=NULL;
free (p);
}
else
printf("can't find %d\n",value);
}
if(p->value==value)
{
if(p==head)//头节点
{
head=head->next;
head->prev=NULL;
free(p);
}
else//中间节点
{
p->prev->next=p->prev->next->next;
p->next->prev=p->next->prev->prev;
free (p);
}
}
return head;
}

Node *dll_insert(Node *head,int n)
{
Node *new;
Node *p=head;
while(p->value<n&&p->next!=NULL)
{
p=p->next;
}
new=(Node*)malloc(sizeof(Node));
if(new==NULL)
{
printf("malloc error!!!\n");
return NULL;
}
new->value=n;

if(p->next==NULL)//尾节点
{
p->next=new;
new->prev=p;
new->next=NULL;
}
else if(p==head)//头节点
{
new->prev=NULL;
new->next=p;
p->prev=new;
head=new;
}
else//中间节点
{
p->prev->next=new;
new->prev=p->prev;
new->next=p;
p->prev=new;
}
return head;
}