A. S->top!=0 B. S->top==0 C. S->top!=n D. S->top==n
A. top->next=S; B. S->next=top;top=S; C. S->next=top->next;top->next=S D. S->next=top;top=S->next;
A. top->next=S; B. S->next=top;top=S; C. S->next=top->next;top->next=S; D. S->next=top;top=S->next;
A. Q->rear-Q->front==n B. Q->rear-Q->front+1==n C. Q->front==Q->rear D. Q->front==Q->rear+1
A. Q->rear-Q->front==n B. Q->rear-Q-front+1==n C. Q->front==Q->rear D. Q->front==Q->rear+1
A. Q->rear==Q->front B. Q->rear==Q->front+1 C. Q->front==(Q->rear+1)%n D. Q->front==(Q->rear-1)%n
A. front=front->next B. rear=rear->next C. rear->next=front D. front->next=rear
A. front=front->next B. S->next=rear;rear=S; C. rear->next=S;rear=S; D. S->next=front;front=S;
A. 3,2,4,1 B. 1,2,3,4 C. 4,2,3,1 D. 4,3,2,1