Array of Pointers

[[Deleted]]

Hi,

I have an array of Pointers like  

Order* m_orders[]

and there is a problem:

 Order is a class containg informations about TP, SL, open time and so on.

I want to sort this array by open time in a function but mql(4) accepts only arrays by reference as parameter so I can't do that.

In C language it is quite simple:

void Sort(Order *pointer, int size)
{
    Order *i, *j, temp;

    for(i = pointer; i < pointer + size; i++)
   {
        for(j = i + 1; j < pointer + size; j++)
        {
            if((*j).OrderDate < (*i).OrderDate)
            {
                temp = *j;
                *j = *i;
                *i = temp;
            }
        }
    }
}

 

 Any tips ?

Thank you 

[Carl Schreiber]

What about using struct and an array of structs?

struct _Orders {
    datetime OrderDate;
    double SL,TG,..;
    int Ticket;
    ...
};
_Orders ArrOrders[];
...
ArrayResize(ArrOrders,5);
...
void sort(_Orders& arr) {
    ...
    if (arr[x].OrderDate < arr[y].OrderDate ) { ... }
}
// NOT TESTED!!

[William Roeder]

MarcoNeri: I want to sort this array by open time in a function but mql(4) accepts only arrays by reference as parameter so I can't do that.
In C language it is quite simple:

1. Play video	Please edit your post. For large amounts of code, attach it.

   ---

2. Why not?
3. It's just as simple in mt4. Even easier and much more efficient if you use an insertion sort. (Never use bubble sort - ever.)
   Not tested

   class Order{
    public: 
      datetime OrderDate(void){return 0;}
   };
   //////////////////////////////////////
   void Sort(Order* &Array[], int size){
      for(int i=1; i < size; ++i){
         Order*   temp = Array[i];
         datetime od   = temp.OrderDate();
         while(i>0 && od < Array[i-1].OrderDate() ) Array[i] = Array[--i];
         Array[i] = temp;
      }
   }

   Not tested
4. A generic approach is to templatize it and provide a comparator.
   Not compiled, not tested

   class OrderByDateAscending{
    public:
      bool IsLess(const Order& LHS, const Order& RHS){
         return LHS.OrderDate() < RHS.OrderDate();
      }
   }
   //////////////////////////////////////
   template <typename C, typename BinaryPredicate>
   void Sort(C* &Array[], int size, BinaryPredicate& comp){
      for(int i=1; i < size; ++i){
         C* temp = Array[i];
         while(i>0 && comp.IsLess(temp, Array[i-1]) ) Array[i] = Array[--i];
         Array[i] = temp;
      }
   }

   Not compiled, not tested

[[Deleted]]

thanks to all !

I will use quicksort !

[William Roeder]

MarcoNeri: I will use quicksort !	What quicksort? Alphabetic Index of MQL4 Functions (600+) - MQL4 forum

[[Deleted]]

WHRoeder:

MarcoNeri: I will use quicksort !	What quicksort? Alphabetic Index of MQL4 Functions (600+) - MQL4 forum

This one:

 Not Tested

void QuickSort(Order* &arr[], uint left, uint right)
{

  uint i = left, j = right;
  Order* tmp;
  Order* pivot = arr[MathAbs((left + right) / 2)];

  /* partition */

  while (i <= j) {
        while (arr[i].GetOrderOpenTime() < pivot.GetOrderOpenTime())
              i++;
        while (arr[j].GetOrderOpenTime() > pivot.GetOrderOpenTime())
              j--;

        if (i <= j) {
              tmp = arr[i];
              arr[i] = arr[j];
              arr[j] = tmp;
              i++;
              j--;
        }
  }

  /* recursion */

  if (left < j)
     QuickSort(arr, left, j);

  if (i< right)
     QuickSort(arr, i, right);

}

 

 Not tested

[William Roeder]

1. What part of using SRC was unclear?
2. Unless you have more than 16 orders, the Insertion sort will be faster.
   

[[Deleted]]

Sorry for using of SRC :

 

class Dummy
{
};

 Now I get it. :-D 

Thank you again.