// demonstration of similarity/difference between templates 
// and polymorphism approaches
// hussein suleman @ AIM @ CS @ UCT
// 16 september 2003

#include <string>
#include "stdafx.h"
#include <conio.h>
#include <time.h>

// some random abstract base class with output and comparison declared
class myData
{
public:
   virtual bool operator<=( myData& x ) = 0;
   virtual void output () = 0;
};

// wrapper for an integer
class myInt : public myData
{
public:
   int data;
   myInt ()   {  data = rand();  }
   virtual bool operator<=( myData& x )
   {
      myData* y = &x;
      myInt* z = ((myInt *)(y));
      return (data <= z->data);
   }
   virtual void output () { printf ("%u\n", data); }
};

// wrapper for a long integer
class myLong : public myData
{
public:
   long data;
   myLong ()   {  data = rand();  }
   virtual bool operator<=( myData& x )
   {
      myData* y = &x;
      myLong* z = ((myLong *)(y));
      return (data >= z->data);
   }
   virtual void output () { printf ("%ul\n", data); }
};

// minimum of 3 items using templates
template <class T>
T& mintemp ( T& a, T& b, T& c )
{
   if (a<=b) if (a<=c) return a;
   if (b<=a) if (b<=c) return b;
   return c;
}

// minimum of 3 items using polymorphism
myData& minpoly ( myData& a, myData& b, myData& c )
{
   if (a<=b) if (a<=c) return a;
   if (b<=a) if (b<=c) return b;
   return c;
}

// MAIN
int _tmain(int argc, _TCHAR* argv[])
{
   // create arrays of 3 random integer and long objects respectively
   srand ((unsigned)time(NULL));
   myInt i[3];
   myLong l[3];

   // output whole arrays
   i[0].output(); i[1].output(); i[2].output();
   l[0].output(); l[1].output(); l[2].output();
   
   // use template function to find minima
   printf ("minimum (template - int) = ");
   mintemp (i[0], i[1], i[2]).output();
   printf ("minimum (template - long) = ");
   mintemp (l[0], l[1], l[2]).output();

   // use polymorphic function to find minima
   printf ("minimum (polymorphism - int) = ");
   minpoly (i[0], i[1], i[2]).output();
   printf ("minimum (polymorphism - long) = ");
   minpoly (l[0], l[1], l[2]).output();

   _getch();
   return 0;
}