I have a fictional class:

template<typename T> class demonstration
{  
    public:
    demonstration(){}
    ...
    T *m_data;
}

At some point in the program's execution, I want to set m_data to a big block of allocated memory and construct an object T there.

At the moment, I've been using this code:

void construct()
{
    *m_data = T();
}

Which I've now realised is probably not the best idea... wont work under certain cirumstances, if T has a private assignment operator for example.

Is there a normal/better way to do what I'm attempting here?