Typed key array

typed.cpp

#include <iostream>
#include <iterator>
#include <type_traits>

enum EnumA {
    A,
    B,
    C,
    D,
    EnumALast
};

enum EnumB {
    Cero,
    Uno,
    Dos,
    Tres,
    Cuatro,
    EnumBLast
};

template <typename TKey, typename TValue, unsigned int N>
class ArrayWithEnumAsKey {

    static_assert(std::is_enum<TKey>::value, "Invalid argument (not enum)");

public:

    class Iterator : public std::iterator<std::input_iterator_tag, TKey, std::ptrdiff_t, TValue*, TValue&> {

    public:
        Iterator(TValue* x) :p(x) {}
        Iterator(const Iterator& mit) : p(mit.p) {}
        Iterator& operator++() {++p; return *this;}
        //Iterator operator++(int) {Iterator tmp(*this); operator++();return tmp;}
        bool operator==(const Iterator& rhs) {return p==rhs.p;}
        bool operator!=(const Iterator& rhs) {return p!=rhs.p;}
        TValue& operator*() {return *p;}

    private:
        TValue *p;

    };

    TValue& operator[](TKey idx) {
        return arr[idx];
    };

    const TValue& operator[](TKey idx) const {
        return arr[idx];
    };

    const size_t size() {
        return N;
    }

    const Iterator begin() {
        return Iterator(arr);
    }

    const Iterator end() {
        return Iterator(arr+N);
    }

private:

    TValue arr[N];

};

int main() {

    ArrayWithEnumAsKey<EnumB, std::string, EnumBLast> test1;

    std::string hola = "test";
    for (auto iter = test1.begin(); iter != test1.end(); ++iter) {
        *iter = hola;
        hola += ".";
    }

    for (auto elem : test1) {
        std::cout << elem << std::endl;
    }

}