写出下面程序执行后的运行结果。#include #include struct NODE {int num;struct NODE *next;};int main(){ struct NODE *p,*q,*r;int sum=0;p=(struct NODE *)malloc(sizeof(struct NODE));q=(struct NODE *)malloc(sizeof(struct NODE));r=(struct NODE *)malloc(sizeof(struct NODE));p->num=1;q->num=2;r->num=3;p->next=q;q->next=r;r->next=NULL;sum+=q->next->num;sum+=p->num;printf("%d",sum);return 0;}