exprops2.hpp

C++ Templates 完全导引范例asics

/* 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.
 */
// addition of two Arrays
template <typename T, typename R1, typename R2>
Array<T,A_Add<T,R1,R2> >
operator+ (Array<T,R1> const& a, Array<T,R2> const& b) {
    return Array<T,A_Add<T,R1,R2> >
           (A_Add<T,R1,R2>(a.rep(),b.rep()));
}

// multiplication of two Arrays
template <typename T, typename R1, typename R2>
Array<T, A_Mult<T,R1,R2> >
operator* (Array<T,R1> const& a, Array<T,R2> const& b) {
    return Array<T,A_Mult<T,R1,R2> >
           (A_Mult<T,R1,R2>(a.rep(), b.rep()));
}

// multiplication of scalar and Array
template <typename T, typename R2>
Array<T, A_Mult<T,A_Scalar<T>,R2> >
operator* (T const& s, Array<T,R2> const& b) {
    return Array<T,A_Mult<T,A_Scalar<T>,R2> >
           (A_Mult<T,A_Scalar<T>,R2>(A_Scalar<T>(s), b.rep()));
}

// multiplication of Array and scalar
// addition of scalar and Array
// addition of Array and scalar
//...