问题详情

有以下程序
#include ＜stdlib.h＞
struct NODE{
int num;
struct NODE *next;};
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(“%dn”,sum);}
执行后的输出结果是
A．3
B．4
C．5
D．6