OrderSelect()?

[macpee]

Which of the two blocks of code is correct?

for (int i=0; i <= OrdersTotal()-1; i++)
     {
      bool Select = OrderSelect(i, SELECT_BY_POS, MODE_TRADES);
     )

and this

for (int i=1; i <= OrdersTotal(); i++)
     {
      bool Select = OrderSelect(i, SELECT_BY_POS, MODE_TRADES);
     )

In other words, is 0 a valid integer for selecting an order by position?

[Fernando Carreiro]

macpee: Which of the two blocks of code is correct?

The order index starts at "0". When in doubt check the documentation. The OrdersTotal documentation even has an example.

Your code however can be simplified as follows (see also OrderSelect documentation):

for( int i=0; i < OrdersTotal(); i++ )
{
   bool Select = OrderSelect( i, SELECT_BY_POS );
};

[William Roeder]

You can also count down.

for(int iPos = OrdersTotal()-1; iPos >= 0; iPos--) if(OrderSelect(iPos, SELECT_BY_POS){ …

In the presence of multiple orders (one EA multiple charts, multiple EAs, manual trading), while you are waiting for the current operation (closing, deleting, modifying) to complete, any number of other operations on other orders could have concurrently happened and changed the position indexing and order count:

1. For non-FIFO (non-US brokers), (or the EA only opens one order per symbol), you can simply count down, in a index loop, and you won't miss orders. Get in the habit of always counting down.
             Loops and Closing or Deleting Orders - MQL4 programming forum

2. For In First Out (FIFO rules — US brokers), and you (potentially) process multiple orders per symbol, you must find the earliest order (count up), close it, and on a successful operation, reprocess all positions.
             CloseOrders by FIFO Rules - Strategy Tester - MQL4 programming forum - Page 2 #16
             MetaTrader 5 platform beta build 2155: MQL5 scope, global Strategy Tester and built-in Virtual Hosting updates - Best Expert Advisors - General - MQL5 programming forum #1.11

3. and check OrderSelect in case later positions were deleted.
             What are Function return values ? How do I use them ? - MQL4 programming forum
             Common Errors in MQL4 Programs and How to Avoid Them - MQL4 Articles

4. and if you (potentially) process multiple orders, must call RefreshRates() after server calls if you want to use, on the next order / server call, the Predefined Variables (Bid/Ask.) Or instead, be direction independent and just use OrderClosePrice().