一个链栈的栈顶指针是top，则执行出栈操作时（栈非空），用x保存被删除结点，则执行

A.x=HS; HS= HS—＞next;

B.x=HS—＞data;

C.HS= HS—＞next; x=HS—＞data;

D.x=HS—＞data; HS= HS—＞next;

A.data[top]=x;top--;

B.data[top]=x;top++;

C.top--; data[top]=x;

D.top++; data[top]=x;

A.x=top->data;top=top->next；

B.top=top->link;x=top-> next；

C.x=top;top=top-> next；

D.x=top-> next；

A.p->next=top; top=top->next;

B.top->next=p;

C.p->next=top->next; top->next=p;

D.p->next=top; top=p;

A.top=top+1;

B.top=top-1;

C.top->next=top;

D.top=top->next;

A.s->top--; *x= s->elem[s->top];

B.*x= s->elem[s->top]; s->top= s->top-1;

C.*x =s->elem[s->top--];

D.*x= s->elem[s->top];s->top--;

A.top++;

B.top--;

C.top=0;

D.top=n;

A.x=lst; lst = lst->next ;

B.x=lst->data

C.lst=lst->next; x=lst->data;

D.x=lst->data; lst= lst->next;