C++ class 模板派生自模板化 class：有没有更好的写法？

Question

I wonder if the following code could be written better:

template< typename DataType >
class MyDerivedClass : public MyBaseClass< std::vector< DataType > >
{
public:
    typedef std::vector< DataType> ListDataType;

    // ...
};

Specifically, I would like to eliminate the extra mention of 'std::vector', but this is of course illegal:

template< typename DataType >
class MyDerivedClass : public MyBaseClass< ListDataType >
{
public:
    typedef std::vector< DataType> ListDataType;

    // ...
};

Any ideas?

Answer 1

If the goal is just to avoid writing std::vector twice, you can define an additional helper template parameter for it.

template< typename DataType, typename U = std::vector<DataType> >
class MyDerivedClass : public MyBaseClass< U >
{
public:
    using ListDataType = U;
    // ...
};