有人看下这个链表哪错了，创建、插入没出问题，删除时出错了。

#include <stdio.h>
#include <stdlib.h> 
#include <string.h> 
struct node
{
    int num;
    struct node *next;
}*p,*q,*head,*temp,*p1,*endpointer,*p2,*p3;

int main()
{
/*create*/
    p=q=p1=p2=head=temp=(struct node*)malloc(sizeof(struct node));
    printf("input num ");scanf("%d",&p->num);
    p->next=NULL;
    while(p->num)
    {
        q=p;
        p=(struct node*)malloc(sizeof(struct node));
        printf("input num ");scanf("%d",&p->num);
        q->next=p;
    }
    q->next=NULL;
    endpointer=q;
    printf("结果:");
    while(temp)
    {
        printf("%2d ",temp->num);
        temp=temp->next;
    }
    putchar('\n');
/*insert*/  
    free(temp);
    temp=(struct node*)malloc(sizeof(struct node));
    printf("input insert num");
    scanf("%d",&temp->num);

    while(p1!=NULL && p1->num<temp->num)
    {
        p=p1;
        p1=p1->next;
    }
    if(head->num>temp->num)/*top*/
    {
        p2=temp;
        temp->next=p1;
    }
    else if(endpointer->num<temp->num)/*end*/
    {
        p->next=temp;
        temp->next=NULL;
        endpointer=temp;
    }
    else /*medium*/
    {
        p->next=temp;
        temp->next=p1;
    }
    head=p2;
    printf("结果:"); 
    while(p2)
    {
        printf("%2d ",p2->num);
        p2=p2->next;
    }
    putchar('\n');
/*delete*/  
    free(temp);free(p1);free(p);
    p1=head;
    int nun;
    printf("input delete num");
    scanf("%d",&nun);
    while(p1->next!=NULL && p1->num!=nun)
    {
        p=p1;
        p1=p1->next;
    }
    if(head->num==nun==p1->num)
    {
        head=p1->next;
    }
    else if(endpointer->num==nun==p1->num)
    {
         p->next=NULL;
    }
    else
    {
        p->next=p1->next;
    }

    printf("结果:"); 
    while(head)
    {
        printf("%2d ",head->num);
        head=head->next;
    }
    putchar('\n');


}

/*delete*/

//free(temp);
//free(p1);
//free(p);
这三行去掉