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c++arraysc++11templatesclass-template

Using typedef types in definition

I have a class as follows,

template<size_t N>
class A 
{
   typedef int(*ARRAY)[N];
   array getArray();

   ARRAY array;
};

Then how can I use the type ARRAY in the definition? I have tried this

template<size_t N>
ARRAY A<N>::getArray()
{
   return array;
}

But, it tells me that ARRAY is not defined.

Solution

  • ARRAY is depended name, therefor you need to use the typename keyword before it, outside the class scope.

    template<size_t N>
typename A<N>::ARRAY A<N>::getArray()
//^^^^^^^^^^^^^
{
   return array;
}

    or using trailing return

    template<size_t N>
auto A<N>::getArray() -> ARRAY
//                 ^^^^^^^^^^^^^
{
   return array;
}

    In addition, you have a typo in your class member declaration. The

    array getArray();

    should be

    ARRAY getArray();

    However, is there any reason that you do not want to use the std::array?