Introsort_pfn/sort_object_ptrs_array.mq5

<EFBFBD><EFBFBD>//+------------------------------------------------------------------+
//|                                       sort_object_ptrs_array.mq5 |
//|                                        Copyright <EFBFBD> 2018, Amr Ali |
//|                             https://www.mql5.com/en/users/amrali |
//+------------------------------------------------------------------+
#include "Introsort.mqh"

//+------------------------------------------------------------------+
//| Templated class                                                  |
//+------------------------------------------------------------------+
template <typename T>
class Foo
  {
public:
                     Foo(void) { payload=(T)10*MathRand()/MathRand(); }
                    ~Foo(void) {   }
   T                 Payload(void) { return payload; }

private:
   T                 payload;
  };

//+------------------------------------------------------------------+
//| Templated compare function for different types of payloads.      |
//+------------------------------------------------------------------+
template <typename T>
bool CompareByPayload(T left, T right)
  {
   return left.Payload() < right.Payload();
  }

// Define multiple pointer types to custom Less function.
typedef bool (*pLessInt) (Foo<int>*, Foo<int>*);
typedef bool (*pLessFloat) (Foo<float>*, Foo<float>*);

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
void OnStart()
  {
   Foo<int>   *objArray1[7];   // array of object pointers
   Foo<float> *objArray2[7];

//--- Generate random data.
   for(int i = 0; i < 7; i++)
     {
      objArray1[i]=new Foo<int>();
      objArray2[i]=new Foo<float>();
     }

//--- Sort the input arrays in-place using a pointer to comparison function less.
   Introsort(objArray1, (pLessInt)CompareByPayload<Foo<int>*>);
   Introsort(objArray2, (pLessFloat)CompareByPayload<Foo<float>*>);

   Print("Integer objects:");
   for(int i = 0; i < 7; i++)
     {
      printf("%d. payload=%s",i,(string)objArray1[i].Payload());
      delete objArray1[i];
     }

   Print("Float objects:");
   for(int i = 0; i < 7; i++)
     {
      printf("%d. payload=%s",i,(string)objArray2[i].Payload());
      delete objArray2[i];
     }

  }
//+------------------------------------------------------------------+