// template_class.cc  a template that needs two classes to instantiate

// this should be in a file  my_class.h

template <class C1, class C2>  // user needs two class types for 'C1' and 'C2'
class My_class
{
  public:
    My_class(void){}
    My_class(C1 Adata1, C2 Adata2) { data1 = Adata1; /*data2 = Adata2;*/}
    // other functions using types C1 and C2
    // using statements such as below put requirements on C1 and C2
    int Get_mode(void)      { return data1.i;    }
    int Get_mode(C2 Adata3) { return Adata3.mode; } 
    // ... 
  protected:
    C1 data1;
    // C2 data2(7); // initialization not allowed here
    // ...
};


// in users main program file
// #include <my_class.h>

class A_class    // users class that will be OK for template type 'C1'
{
  public:
    A_class(void) { i = 3; }
    int i;
};

class B_class   // users class that will be OK for template type 'C2'
{
  public:
    B_class(int Amode) { mode = Amode; stuff = 0.0; }
    int mode;
  private:
    double stuff;
};


#include <iostream>
using namespace std;

int main(void)
{
  A_class AA;       // we need an object of type A_class
  B_class B1(7);    // we need an object of type B_class
  B_class B2(15);   // another object
 
  My_class<A_class, B_class> stuff;  // 'stuff' is the instantiated template

  cout << "stuff.Get_mode(B1) " << stuff.Get_mode(B1) << endl;

  // now instantiate the template again to get the object 'things'

  My_class<A_class, B_class> things(AA, B2); // using the constructor to
                                             // pass objects 'AA' and 'B2"

  cout << "things.Get_mode() " << things.Get_mode() << endl;

  return 0;
}
// output from execution is:
// stuff.Get_mode(B1) 7
// things.Get_mode() 3