C语言经典算法之双链表正排序 include, C语言, 经典

苹果也疯狂

#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>
struct list{
  intdata;
struct list *next;
struct list *pre;
  };
typedef struct list node;
typedef node *link;
link front=NULL,rear,ptr,head=NULL;
link push(int item){
link newnode=malloc(sizeof(node));
newnode->data=item;
if(head==NULL)
{
head=newnode;
head->next=NULL;
head->pre=NULL;
rear=head;
}
else
{
rear->next=newnode;
newnode->pre=rear;
newnode->next=NULL;
rear=newnode;
}
return head;
}
void makenull(){           
front=NULL;
rear=NULL;
}
empty(){
if(front==NULL)
  return 1;
else
  return 0;
  }
int tops(){
  if(empty())
   return NULL;
  else
    return rear->data;
   }
void pop(){
  if(empty())
   printf("stack is empty!\n");
  else
   rear=rear->pre;
   }
void display(link l){
   link p;
   p=l;
   while(p!=NULL){
     printf("%d->",p->data);
     p=p->next;
    }
}
void main(){
int n,i;
printf("input your firstdata!\n");
scanf("%d",&n);
front=push(n);
  /*another data*/
for(i=0;i<3;i++)
{
printf("input:\n");
scanf("%d",&n);
push(n);
}
ptr=front;
display(ptr);
printf("\n Please enter any key to pop");
getch();
pop();
ptr=front;
display(ptr);
getch();
}