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Acknowledging CGAL
CGAL 5.4 - STL Extensions for CGAL
STL_Extension/Default.cpp
#include <CGAL/Default.h>
#include <CGAL/use.h>
// A is a concrete type
struct
A {};
void
use_a(A) {}
// B is the template class which has 2 template parameters
// with default arguments : A and int.
template
<
typename
A1_ = A,
typename
A2 =
int
>
struct
B
{
B()
: a1()
{}
// Note that it is also possible to use CGAL::Default
// instead of A as the default argument for A1_ above.
// Extract the desired type for A1 :
typedef
typename
CGAL::Default::Get<A1_, A>::type
A1;
A1 a1;
};
int
main ()
{
B<CGAL::Default, double> b;
use_a(b.a1);
// It is really of type A.
}