while loop question

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Hi, 


After I added the code below to my EA, my program just hanged without an error message. Can someone explain what is wrong with it?

void OnTick()
  {
........... some code
   while(OrdersTotal()==1)
     {
      if(BlueCurrent>RedCurrant)
        {
         ExitSellOrder();
         break;
        }
      if(BluePrevious>Red Previous)
        {
         ExitBuyOrder();
         break;
        }
     }
.......  some code
  }

Thanks

 
drinkyd:

Hi, 


After I added the code below to my EA, my program just hanged without an error message. Can someone explain what is wrong with it?

Thanks

Why do you need that loop, which will not change until you get a new tick, which you prevent with that loop?

*- if you need the execution to be done when one order exists only, change the while to if statement.
  
void OnTick(){
   ⋮
   while(OrdersTotal()==1){
      if(BlueCurrent>RedCurrant){   ExitSellOrder(); break; }
      if(BluePrevious>Red Previous){ ExitBuyOrder(); break; }
   }
   ⋮
  1. If both your if statements are false, you have an infinite loop.

  2. Using OrdersTotal (or OrdersHistoryTotal) directly and/or no Magic number filtering on your OrderSelect loop means your code is incompatible with every EA (including itself on other charts and manual trading.)
              Symbol Doesn't equal Ordersymbol when another currency is added to another seperate chart . - MQL4 programming forum
              MagicNumber: "Magic" Identifier of the Order - MQL4 Articles

  3. 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:
    1. For non-FIFO (non-US brokers), (or the EA only opens one order per symbol,) you can simply count down, in a position loop, and you won't miss orders. Get in the habit of always counting down.
                Loops and Closing or Deleting Orders - MQL4 programming forum
      For In First Out (FIFO rules-US brokers,) and you (potentially) process multiple orders per symbol, you must find the earliest order, close it, and on a successful operation, reprocess all remaining positions.
                CloseOrders by FIFO Rules - Strategy Tester - MQL4 programming forum - Page 2 #16

    2. and check OrderSelect in case earlier 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
    3. 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 (be direction independent and use) OrderClosePrice().

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