The following code example is taken from the book
 
  C++ Templates - The Complete Guide
 by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002
 
  © Copyright David Vandevoorde and Nicolai M. Josuttis 2002
template<typename T>
class AccumulationTraits;
template<>
class AccumulationTraits<char> {
  public:
    typedef int AccT;
};
template<>
class AccumulationTraits<short> {
  public:
    typedef int AccT;
};
template<>
class AccumulationTraits<int> {
  public:
    typedef long AccT;
};
template<>
class AccumulationTraits<unsigned int> {
  public:
    typedef unsigned long AccT;
};
template<>
class AccumulationTraits<float> {
  public:
    typedef double AccT;
};