how to determine class type in template defintion

jehudi

Problem is how to implement the following:

template<class T>; class t {
    T a_function(T x, T y) {
        // if T is class A
        // return function_for_A(x, y);
        // if T is class B
        // return function_for_B(x, y);
    }
}

Some libraries like BLAS/LAPACK use different function name for different data types doing the same thing (function_for_A and function_for_B in above), i.e. there is no overloading.  I want to build a template class to overload these functions.  Is this possible?

Thanks for reply and suggestions.

柳五随风

通过WRAPPER实现的方法如下:
TEMPLATE  <CLASS T>;
CLASS VirtualBase {
  PUBLIC:
     VIRTUAL T  A_FUNCTION(T x, T y)=0;
  ...
};

TEMPLATE <CLASS T>;
CLASS WrapperA: PUBLIC VirtualBase<CLASS T>;
{
  PUBLIC:
    T A_FUNCTION(T x, T y) {  RETURN function_for_A(x, y); }
  ...
};


TEMPLATE <CLASS t>;
CLASS WrapperB: PUBLIC VirtualBase<CLASS T>;
{
  PUBLIC:
    T A_FUNCTION(T x, T y) {  RETURN function_for_B(x, y); }
  ...
};

jehudi

Thanks a lot.

But I am afraid this is not what I want, because in instantiating the objects I would have to use (if I am not wrong):

e.g.,
WrapperA<float>; f;
WrapperB<double>; d;

what I want is:
t<float>; f;
t<double>; d;

and the function a_function should work respectively for double and float.

jehudi

Thanks a lot.

But I am afraid this is not what I want, because in instantiating the objects I would have to use (if I am not wrong):

e.g.,
WrapperA<float>; f;
WrapperB<double>; d;

what I want is:
t<float>; f;
t<double>; d;

and the function a_function should work respectively for double and float.

柳五随风

摸版类的特殊华可以实现你的需求.
不过这样失去了使用摸版的意义.