Ez miért nem fordul le? C++

//main.cpp

#include<iostream>

#include<string>

using std::cout;

using std::string;

template<class T1, const unsigned short size = 11> class cProba{

public:

cProba(const T1);

~cProba();

T1 operator[](const unsigned short)const;

private:

T1 i_data[size];

protected:

};

template<class T1, const unsigned short size> cProba<T1, size>::cProba(const T1 data){

for(unsigned short i = 0; i < size; ++i)

this->i_data[i] = data;

}

template<class T1, const unsigned short size> cProba<T1, size>::~cProba() {}

template<class T1, const unsigned short size> T1 cProba<T1, size>::operator[](const unsigned short idx)const {return this->i_data[idx];}

template<int data, unsigned short size> class cIntProba: cProba<int, size>{

public:

cIntProba();

~cIntProba();

private:

protected:

};

template<int data, unsigned short size> cIntProba<data, size>::cIntProba(): cProba<int, size>(data) {}

template<int data, unsigned short size> cIntProba<data, size>::~cIntProba() {}

int main(){

cProba<unsigned short, 8> Proba1(8);

cProba<string, 4> Proba2("Welcome");

cIntProba<18, 14> IntProba;

cout << Proba1[0] << '\n'

<< Proba2[3] << '\n'

<< IntProba[13];

return 0;

}