有以下程序
#inCluDE
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(“%D\n”,sum);
}
执行后的输出结果是
A．3
B．4
C．5
D．6