Hi all,
As some book tells, I try the following example of expression
template.
template < typename LeftOpd, typename Op, typename RightOpd >
struct LOP
{
LeftOpd lod;
RightOpd rod;
LOP(LeftOpd lhs, RightOpd rhs): lod(lhs), rod(rhs) {}
ADT operator[](const unsigned int i)
{
return Op::apply(lod[i], rod[i]);
}
};
struct Plus
{
static double apply( double a, double b) { return a+b; }
};
template <typename LeftOpd>
LOP< LeftOpd, Plus, Vec > operator+(LeftOpd a, Vec b)
{
return LOP<LeftOpd, Plus, Vec>(a, b);
};
It is a *very* simple example. I am trying to modify it. I have
written my vector class (a template class, says MyVec<T>). So here
Plus and opeator+ should also be modified to a template structure and
template function. I try the following code(I am sorry, I really have
no idea how to do it)
template < typename LeftOpd, typename Op<typename ADT>, typename
RightOpd >
struct LOP
{
LeftOpd lod;
RightOpd rod;
LOP(LeftOpd lhs, RightOpd rhs): lod(lhs), rod(rhs) {}
ADT operator[](const unsigned int i)
{
return Op<ADT>::apply(lod[i], rod[i]);
}
};
template <typename ADT>
struct Plus
{
static ADT apply( ADT a, ADT b) { return a+b; }
};
template <typename LeftOpd, typename ADT>
LOP< LeftOpd, Plus<ADT>, MyVec<ADT> > operator+(LeftOpd a, MyVec<ADT>
b)
{
return LOP<LeftOpd, Plus<ADT>, MyVec<ADT> >(a, b);
};
The code don't work. I am looking for your help.
BTW, I have also defined my Matrix class. I would like to generalize
the expression template. For instance, I hope the following code works
with the help of expression template
MyMat<double> M(10,10);
MyVec<double> V(10); // a column vector
(M*V + 2.3*M)*M
Any idea?
