Why are 'top' and 'pop' seen as undeclared identifiers when I subclass the STL stack class?

Question

I'm feeling rather stupid - must be missing something silly --- I wanted to subclass the generic STL stack class so that I could extend it with a combined top followed by pop operation but my compiler is telling me that both top and pop are undeclared identifiers.

template <typename T>
class MyStack : public stack<T>
{
   public:
      T PopTop()  // Convenience - combined top and pop in one go
         {
            T result = top();
            pop();
            return result;
         }
};

I note that I can fix this problem by writing

   T result = stack<T>::top();

but why isn't top seen automatically given the stack class is directly inherited?

Thanks in advance

Answer 1

首先，不要从std类继承，而是使用私有成员（组合）和委托函数 - 这是一个常见的警告。

话虽如此，错误是因为在有关后代类的 ADL 查找中不考虑具有模板参数的基类。using stack<T>::pop;对于计划在 中使用的每个函数，您可能有类似的声明MyStack。