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template<class A=int, class B=float, class C=double> class SomeClass;

Is it possible to specify only the last parameter with something like: SomeClass<C=long long int> ?

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    No, no named parameters so they have to be given in order. Commented Apr 3, 2018 at 12:12
  • you can apply similar tricks as with function parameters (eg write a SomeClassWithCasFirstParam wrapper that passes the desired defaults to the implementation) Commented Apr 3, 2018 at 12:19
  • Not out of the box, no. The Boost devs have a remarkable workaround to this in their Phoenix and Spirit libraries. Commented Apr 3, 2018 at 12:42
  • It is possible with a policy classes. But it requires some metaprogrammng. Commented Apr 3, 2018 at 16:07

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In c++, is it possible to specify part of the parameters for a template class

Yes. If you don't specify all template parameters, then the unspecified ones will have the default (if a default has been specified).

Is it possible to specify only the last parameter

Not as such. (Just like non-template parameters,) Template parameters are positional. It is not possible to specify parameters after unspecified parameters.

You can work around this using a template alias:

template<class C=double, class A=int, class B=float> using PermutedSomeClass = SomeClass<A, B, C>; PermutedSomeClass<long long> // same as SomeClass<int, float, long long>
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