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

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
void OnStart()
  {
   // Sorting string array (ascending order - default)
   string stringArray[] = {"cherry", "apple", "date", "banana"};
   Introsort(stringArray);
   ArrayPrint(stringArray);

   // Define a pointer type to custom Less function.
   typedef bool (*pDescending)(string left, string right);

   // Sorting string array (descending order)
   Introsort(stringArray, (pDescending)Descending);
   ArrayPrint(stringArray);
  }
//+------------------------------------------------------------------+

// Custom Less function to sort in descending order.
bool Descending(string left, string right)
  { return left > right;  }