Re: reference type as template argument

From:

"Alf P. Steinbach" <alfps@start.no>

Newsgroups:

comp.lang.c++

Date:

Wed, 14 May 2008 18:36:03 +0200

Message-ID:

<qridnWXXN6BribbVnZ2dnUVZ_sDinZ2d@posted.comnet>

* subramanian100in@yahoo.com, India:

consider
template<typename T> Test
{
// ...
};

We can have a pointer type as argument to a template class. For
example, we can have,
int x = 100;
Test<int*> obj(&x); // assuming a suitable ctor exists

But we cannot have reference type as template argument. This is
because reference cannot be assigned (in the overloaded assignment
operator) in the ordinary sense - that is, a reference cannot be
reseated. So, we cannot instantiate a template class with reference
type as argument. Is this understanding of mine, is correct ?

#include <iostream>
#include <ostream>

template< typename T >
struct X
{
     T v;
     X( T v_ ): v(v_) {}
};

int main()
{
     int y = 41;
     X<int&> r( y );
     r.v = 42;
     std::cout << y << std::endl;
}

Cheerio, & hth.,

- Alf

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