CODEWITHSUNDEEP
c++templatesc++11
Dejwi
Dejwi

Reputation: 4487

std::array with unspecialized template class

Is it possible to pass somehow unspecialized template class as a template parameter to std::array? Something similar to that:

template <class T>
class Field{
};

std::array<Field> a;

Or I have to define some BaseField, and sublass it as a IntField, StringField, FloatField.... ?

Upvotes: 1

Views: 209

Answers (3)

juanchopanza
juanchopanza

Reputation: 227370

You can get pretty close with C++11, using an alias template:

template <typename T>
struct Field {}; 

template <typename T>
using FieldArray5 = std::array<Field<T>,5>;

int main() {

  FieldArray5<int> a0;

}

But bear in mind that std::array needs a template argument for the size too.

Upvotes: 2

Jerry Coffin
Jerry Coffin

Reputation: 490088

You can write a template that takes a template as a parameter (aka, a template template parameter). The template has to be written specifically to take a template as a parameter to allow it though, and std::array isn't specified to do that.

Upvotes: 4

Daniel
Daniel

Reputation: 31569

If you want an std::array to hold different types, it can only be done through polymorphism. You can also use boost::any that hides that polymorphism from you but still implements it.

Upvotes: 1

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