双向链表循环、插入、删除

#include "stdio.h"
#include "stdlib.h"

typedef int zlp;

typedef struct Node{
	zlp data;
	struct Node *pre,*next;
}Linklist;

Linklist *creat(){
	Linklist *head = (Linklist*)malloc(sizeof(Linklist));
	Linklist *curr = head;
	for(int i=0;i<6;i++){
		Linklist *temp = (Linklist*)malloc(sizeof(Linklist));
		temp->data=i;
		curr->next=temp;
		temp->pre=curr;
		curr=temp;
	}
	curr->next=NULL;
	return head;
}
Linklist *insert(Linklist *a,int pos,int num){
	Linklist *curr = a;
	while(pos>=1){
		curr = curr->next;
		--pos;
	}
	
	Linklist *temp = (Linklist*)malloc(sizeof(Linklist));
    temp->data=num;
    temp->next=curr->next;
    curr->next->pre=temp;
    temp->pre=curr;
    curr->next=temp;
	return a;
}
Linklist *dele(Linklist *a,int pos){
	Linklist *curr=a;
	while(pos>=1){
		curr=curr->next;
		--pos;
	}
	Linklist *q = (Linklist*)malloc(sizeof(Linklist));
	q = curr->next;
	curr->next=q->next;
	q->next->pre=curr;
	return a;
}
void display(Linklist* a){
	Linklist *curr = a->next;
	while(curr!=NULL){
		printf("%d ",curr->data);
		curr=curr->next;	
	}			
	printf("\n");
}

int main(){
	Linklist *a = creat();
	display(a);
	insert(a,1,20);
	display(a);
	dele(a,1);
	display(a);
	return 0;
	
}