给个在模板内使用typename的例子，谢谢

[toldds]

给个在模板内使用typename的例子，谢谢

[sevecol]

Use this keyword only in template definitions. This keyword tells the compiler that an unknown identifier is a type. For example:

template<typename F,typename H=F,typename T=F>
class DTypeList
{
public:
typedef F List;
typedef TypeList<Int2Type<H::Head::value-T::Head::value>,typename DTypeList<List,H,typename T::Tail>::Result> Result;
};

template<typename F,typename T>
class DTypeList<F,T,NullType>
{
public:
typedef F List;
typedef typename DTypeList<F,typename T::Tail,F>::Result Result;
};

template<typename F,typename T>
class DTypeList<F,NullType,T>
{
public:
typedef F List;
typedef NullType Result;
};