tree.h中
template<typename Functor, char Operator>
class binary_operation : public node
{
// ... unimportant details ...
unsigned evaluate() const;
void print(std::ostream& os) const;
};
typedef binary_operation<std::plus<unsigned>, '+'> addition;
typedef binary_operation<std::multiplies<unsigned>, '*'> multiplication;
// ...
tree.cpp
template<typename Functor, char Operator>
unsigned binary_operation<Functor, Operator>::evaluate() const
{
// ... unimportant details ...
}
template<typename Functor, char Operator>
void binary_operation<Functor, Operator>::print(std::ostream& os) const
{
// ... unimportant details ...
}
template class binary_operation<std::plus<unsigned>, '+'>;
template class binary_operation<std::multiplies<unsigned>, '*'>;
// ...
如您所见,头文件中的typedef与实现文件中的显式类模板实例之间存在一些代码重复.有没有办法摆脱不需要像往常一样在头文件中放置"所有"的重复？