I know that in C++ we can do this:
class A {} a;
This makes an object of type A
named a
. It's equivalent to:
A a;
I was wondering how I would do this with templates. For example:
template <typename T> struct N {} <int> n;
This doesn't compile, but you get the idea. How would I specify the template arguments to an object created inline with its class definition? Is this even possible?
An explicit specialization of a function template is inline only if it is declared with the inline specifier (or defined as deleted), it doesn't matter if the primary template is inline.
A template argument for a template template parameter is the name of a class template. When the compiler tries to find a template to match the template template argument, it only considers primary class templates. (A primary template is the template that is being specialized.)
Class Template Argument Deduction (CTAD) is a C++17 Core Language feature that reduces code verbosity. C++17's Standard Library also supports CTAD, so after upgrading your toolset, you can take advantage of this new feature when using STL types like std::pair and std::vector.
There is no difference between using <typename T> OR <class T> ; i.e. it is a convention used by C++ programmers.
The stuff after the closing }
is called an init-declarator-list
according to the standard.
14.3 explicitly forbids them to be used in template class declarations:
In a template-declaration, explicit specialization, or explicit instantiation the init-declarator-list in the dec- laration shall contain at most one declarator. When such a declaration is used to declare a class template, no declarator is permitted.
I don't think you can do that. The form you mentioned, for structures and classes is kept, from my understanding, for backward compatibility with c - where you could do that for structs.
Nice idea, though :)
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