why it ebdless loop

Question

#include<stdio.h>
struct node
{
int date;
struct node *next;
};
typedef struct node linknode;
typedef linknode *linklist;
int main()
{
linklist head,tail,q;
printf("input a.numeber(以空格分隔，以0作为结束):\n");
int n;
scanf("%d",&n);
while(n!=0)
{
q=(linklist)malloc(sizeof(linknode));
q->date=n;
if(head==NULL)
head=tail=q;
else
{
tail->next=q;
tail=q;
}
scanf("%d",&n);
}
if(tail!=NULL)
tail->next=NULL;
linklist p=head;
while(p!=NULL)
{
printf("%5d",p->date);
p->next;
}
return 0;
}

Answer 1

while(p!=NULL)
p will never be NULL
===
p = p->next;
instead
p->next;

Answer 2

head needs to be set to NULL or nullptr, if you want to enter this decade. The if(head==NULL) statement will compare with whatever junk was left by the previous program so your list will be random memory values.

You also need to fix the p->next; statement as pointed out already.