Question

_{(*i have to use my array struct, and it has to be dynamical)}

I want the Array struct to be filled with Expe class objects. I`m using Templates but somehow my struct header doesn’t recognize the template I have created.

Struct header:

template <class T>;
struct Arr{
    int days;
    T * M;
};
typedef Arr* Array;

Struct cpp:

void constr(Array &o){
    //Construct of 31*1 Matrix
    o=new Arr;
    o->days = 31;
    o->M = new T[o->days];

It should be fine I think, but I get error:

..\ListStruc.cpp:26:13: error: expected type-specifier before 'T'

Answer 1

You have a semicolon between template<class T> and struct Arr, which doesn’t belong there. So change it to

template <class T> struct Arr{ int days; T * M; };

Furthermore Arr is a template and therefore you can’t typedef Arr* to Array, only Arr<someConcreteType>*.

Last template functions must be implemented in the header and, as mentioned you typedef doesn’t work so put constr in a header and change it to:

template<class T> void constr(Arr<T>*& o){
  o=new Arr<T>;
  o->days = 31;
  o->M = new T[o->days];

There might be other problems, but that is what I can see from the question.

Of course there are problems with your code apart from the compilation (violation of the rule of three and lack of exception safety).