1106

带表头的双向循环链表

#include <stdio.h>

#include <stdlib.h>


struct node
{
int num;
struct node *prior, *next;
};


typedef struct node Node;
typedef struct node * Dbllink;


void create_newnode(Dbllink *new_node);


void create_link(Dbllink * head)
{
create_newnode(head);
(*head)->next = (*head)->prior = *head;
}


void insert_node_head(Dbllink * head,Dbllink *new_node)
{
    (*new_node)->next = (*head)->next;
    (*new_node)->prior = *head;
(*head)->next->prior = *new_node;
(*head)->next = *new_node;
}


void display_node(Dbllink *head)
{
Dbllink tmp;
tmp = (*head)->next;


if(tmp == *head)
{
printf("the link is empty!\n");
}


while(tmp != *head)
{
printf("num = %d\n",tmp->num);
tmp = tmp->next;
}
}


void is_malloc_ok(Dbllink new_node)
{
     if(new_node == NULL)
{
printf("malloc error!\n");
exit(-1);
}
}


void create_newnode(Dbllink * new_node)
{
*new_node = (Dbllink) malloc(sizeof(Node));
is_malloc_ok(*new_node);
}


void insert_node_tail(Dbllink *head,Dbllink new_node)
{
    Dbllink tmp;
    new_node->prior = (*head)->prior;
    new_node->next = *head;
(*head)->prior->next = new_node;
(*head)->prior = new_node;
}


void insert_node_mid(Dbllink *head,Dbllink *new_node,int num)
{
    Dbllink tmp;
tmp = (*head)->next;
    
if(*head == (*head)->next)
{
   (*new_node)->next = (*head)->next;
   (*new_node)->prior = *head;
(*head)->next->prior = *new_node;
(*head)->next = *new_node;
return;
}
else
{
    while(tmp->num < num && tmp->next != *head)
    {
            tmp = tmp->next;
    }
        if(tmp->next != *head)
{
(*new_node)->next = tmp;
(*new_node)->prior = tmp->prior;
tmp->prior->next = *new_node;
tmp->prior = *new_node;
}
else
{
if(tmp->num < num)
{
(*new_node)->next = tmp->next;
(*new_node)->piror = tmp;
tmp->next->piror = *new_node;
tmp->next = *new_node;
}
/* else
{
p->next = new_node;
new_node->next = tmp;
}*/
}
}
}
/*
void delete_node(Dbllink *head,int num)
{
Dbllink tmp;
Dbllink p;
tmp = p = *head;


if(NULL == *head)
{
printf("link is empty!\n");
return;
}


while(tmp->num != num && tmp->next != NULL)
{
p = tmp;
tmp = tmp->next;
}


if(tmp->num == num)
{
        if(tmp == *head)
{
            *head = tmp->next;
free(tmp);
}
else
{
p->next = tmp->next;
free(tmp);
}
}
else
{
printf("no such node!\n");
}
}


void release(Dbllink *head)
{
Dbllink tmp = NULL;


tmp = (*head)->next;


while(tmp != *head)
{
(*head)->next = tmp->next;
free(tmp);
tmp = (*head)->next;
}
}


void revers_link(Dbllink *head)
{
Dbllink p1;
Dbllink p2;
Dbllink p3;


p3 = *head;


if(*head == NULL)
{
printf("the link is empty!\n");
return;
}
if(p3->next == NULL)
{
printf("this link has only one element!\n");
return;
}


p2 = p3->next;


if(p2->next == NULL)
{
p3->next = NULL;
*head =p2;
return;
}


p1 = p2->next;


while(p1->next != NULL)
{
p2->next = p3;
p3 = p2;
p2 = p1;
p1 = p1->next;
}
p2->next = p3;
p1->next = p2;
(*head)->next = NULL;
*head = p1;
}*/


int main()
{
    Dbllink head = NULL;
    Dbllink new_node = NULL;
    int i;
int num;


create_link(&head);


for(i = 0; i < 10;i++)
{
        create_newnode(&new_node);
new_node->num = i;
// insert_node_head(&head,&new_node);
insert_node_tail(&head,new_node);
}


printf("please input a num!\n");
scanf("%d",&num);


create_newnode(&new_node);
new_node->num =  num;


insert_node_mid(&head,*new_node,num);
    
// delete_node(&head,num);


display_node(&head);


// revers_link(&head);


// release(&head);


// display_node(head);
    return 0;
}