Expert Advisor Programming by Andrew R. Young

Advanced Order Placement
if(BuyStopLoss > 0 && BuyStopLoss > LowerStopLevel)
{
BuyStopLoss = LowerStopLevel - MinStop;
}
if(BuyTakeProfit > 0 && BuyTakeProfit < UpperStopLevel)
{
BuyTakeProfit = UpperStopLevel + MinStop;
}
// Place pending order
if(IsTradeContextBusy()) Sleep(10);
BuyTicket = OrderSend(Symbol(),OP_BUYSTOP,LotSize,PendingPrice,UseSlippage,
BuyStopLoss,BuyTakeProfit,"Buy Stop Order",MagicNumber,0,Green);
// Error handling
if(BuyTicket == -1)
{
ErrorCode = GetLastError();
ErrDesc = ErrorDescription(ErrorCode);
ErrAlert = StringConcatenate("Open Buy Stop Order - Error ",ErrorCode,
": ",ErrDesc);
Alert(ErrAlert);
}
ErrLog = StringConcatenate("Ask: ",Ask," Lots: ",LotSize," Price: ",PendingPrice,
" Stop: ",BuyStopLoss," Profit: ",BuyTakeProfit);
Print(ErrLog);
SellTicket = 0;
First, we calculate the upper stop level. We then calculate and verify our pending order price, which
is stored in PendingPrice. We then recalculate UpperStopLevel and calculate the LowerStopLevel
so that they are relative to the pending order price. Note that we do not need to use the Ask or Bid
prices, or figure in the spread when verifying the stop loss and take profit prices.
Finally, we place our pending order using OrderSend(), placing the stop loss and take profit along
with it. We have the standard error handling function to deal with order placement errors.
Despite all the extra code, these expert advisors are using the same strategy as the one at the end of
chapter 2. This code simply has extra features for calculating and verifying lot size, stop levels, stop
loss, take profit and pending order prices. We've also added trade context checks and error handling
code. In the next chapter, we'll learn how to create functions so we can reuse and simplify this code.
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