给定程序中,函数fun的功能是:统计出带有头结点的单向链表中结点的个数,存放在形参n所指的存储单元中。请在程序的下划线处填入正确的内容并把下划线删除,使程序得出正确的结果。注意:源程序存放在考生文件夹下的BLANK1.C中。不得增行或删行,也不得更改程序的结构!给定源程序:#include#include#define N 8typedef struct list{ int data;struct list *next;} SLIST;SLIST *creatlist(int *a);void outlist(SLIST *);void fun( SLIST *h, int *n){ SLIST *p;/**********found**********/___1___=0;p=h->next;while(p){ (*n)++;/**********found**********/p=p->___2___;}}main(){ SLIST *head;int a[N]={12,87,45,32,91,16,20,48}, num;head=creatlist(a); outlist(head);/**********found**********/fun(___3___, &num);printf("\nnumber=%d\n",num);}SLIST *creatlist(int a[]){ SLIST *h,*p,*q; int i;h=p=(SLIST *)malloc(sizeof(SLIST));for(i=0; i{ q=(SLIST *)malloc(sizeof(SLIST));q->data=a[i]; p->next=q; p=q;}p->next=0;return h;}void outlist(SLIST *h){ SLIST *p;p=h->next;if (p==NULL) printf("The list is NULL!\n");else{ printf("\nHead ");do{ printf("->%d",p->data); p=p->next; }while(p!=NULL);printf("->End\n");}}