def peek(self): # 查看栈顶的对象,但不移除 if self.isEmpty(): raise StackException('StackUnderflow def pop(self): # 移除栈顶对象,并返回该对象的值 if self.isEmpty(): raise StackException('StackUnderflow
1]; ref2_t *top = stack; + if (ref_stack_count(&o_stack) < 2)+ return_error(gs_error_stackunderflow