duo5.hpp

C++ Templates 完全导引范例

/* The following code example is taken from the book
 * "C++ Templates - The Complete Guide"
 * by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002
 *
 * (C) Copyright David Vandevoorde and Nicolai M. Josuttis 2002.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include "typeop.hpp" 

// return Nth value of variable duo
template <int N, typename A, typename B> 
inline
typename TypeOp<typename DuoT<N, Duo<A, B> >::ResultT>::RefT
val(Duo<A, B>& d)
{
    return DuoValue<N, Duo<A, B> >::get(d);
}

// return Nth value of constant duo
template <int N, typename A, typename B> 
inline
typename TypeOp<typename DuoT<N, Duo<A, B> >::ResultT>::RefConstT
val(Duo<A, B> const& d)
{
    return DuoValue<N, Duo<A, B> >::get(d);
}