array.h
template <class Type> class Array {
        Type* data;
        int   size;
    public:
        Array(int sz);
        int GetSize();
};

array.cc
template <class Type> Array<Type>::Array(int sz)
    {size = sz; data = new Type[size];}
template <class Type> int Array<Type>::GetSize()
    {return size;}

file1.cc
#include "array.h"
struct Foo {int data;};
Array<Foo> File1Data(10);

file2.cc
#include "array.h"
struct Foo {double data;};
Array<Foo> File2Data(20);