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In this thread I would like to quickly analyze a simple Expert Adviser.
We will have a quick look at it’s functionality, but most importantly, we will familiarize ourselves with integral blocks, which can be found in any EA for MT4. So, sit back and enjoy our little journey.Code
//+------------------------------------------------------------------+ //| My_First_EA.mq4 | //| Kirill | //| StockProgrammer@mail.ru | //+------------------------------------------------------------------+ #property copyright "Kirill" #property link "StockProgrammer@mail.ru" //---- input parameters extern double TakeProfit=350.0; extern double Lots=0.1; extern double TrailingStop=35.0; //+------------------------------------------------------------------+ //| expert initialization function | //+------------------------------------------------------------------+ int init() { //---- //---- return(0); } //+------------------------------------------------------------------+ //| expert deinitialization function | //+------------------------------------------------------------------+ int deinit() { //---- //---- return(0); } int Crossed (double line1 , double line2) { static int last_direction = 0; static int current_dirction = 0; if(line1>line2)current_dirction = 1; //up if(line1<line2)current_dirction = 2; //down if(current_dirction != last_direction) //changed { last_direction = current_dirction; return (last_direction); } else { return (0); } } //+------------------------------------------------------------------+ //| expert start function | //+------------------------------------------------------------------+ int start() { //---- int cnt, ticket, total; double shortEma, longEma; if(Bars<100) { Print("bars less than 100"); return(0); } if(TakeProfit<10) { Print("TakeProfit less than 10"); return(0); // check TakeProfit } shortEma = iMA(NULL,0,8,0,MODE_EMA,PRICE_CLOSE,0); longEma = iMA(NULL,0,13,0,MODE_EMA,PRICE_CLOSE,0); int isCrossed = Crossed (shortEma,longEma); total = OrdersTotal(); if(total < 1) { if(isCrossed == 1) { ticket=OrderSend(Symbol(),OP_BUY,Lots,Ask,3,0,Ask+TakeProfit*Point, "My EA",12345,0,Green); if(ticket>0) { if(OrderSelect(ticket,SELECT_BY_TICKET,MODE_TRADES)) Print("BUY order opened : ",OrderOpenPrice()); } else Print("Error opening BUY order : ",GetLastError()); return(0); } if(isCrossed == 2) { ticket=OrderSend(Symbol(),OP_SELL,Lots,Bid,3,0, Bid-TakeProfit*Point,"My EA",12345,0,Red); if(ticket>0) { if(OrderSelect(ticket,SELECT_BY_TICKET,MODE_TRADES)) Print("SELL order opened : ",OrderOpenPrice()); } else Print("Error opening SELL order : ",GetLastError()); return(0); } return(0); } for(cnt=0;cnt<total;cnt++) { OrderSelect(cnt, SELECT_BY_POS, MODE_TRADES); if(OrderType()<=OP_SELL && OrderSymbol()==Symbol()) { if(OrderType()==OP_BUY) // long position is opened { // should it be closed? if(isCrossed == 2) { OrderClose(OrderTicket(),OrderLots(),Bid,3,Violet); // close position return(0); // exit } // check for trailing stop if(TrailingStop>0) { if(Bid-OrderOpenPrice()>Point*TrailingStop) { if(OrderStopLoss()<Bid-Point*TrailingStop) { OrderModify(OrderTicket(),OrderOpenPrice(),Bid-Point*TrailingStop,OrderTakeProfit(),0,Green); return(0); } } } } else // go to short position { // should it be closed? if(isCrossed == 1) { OrderClose(OrderTicket(),OrderLots(),Ask,3,Violet); // close position return(0); // exit } // check for trailing stop if(TrailingStop>0) { if((OrderOpenPrice()-Ask)>(Point*TrailingStop)) { if((OrderStopLoss()>(Ask+Point*TrailingStop)) || (OrderStopLoss()==0)) { OrderModify(OrderTicket(),OrderOpenPrice(),Ask+Point*TrailingStop,OrderTakeProfit(),0,Red); return(0); } } } } } } return(0); } //+------------------------------------------------------------------+The idea behind our expert advisor.
Before digging into cracking our code we have to explain the idea behind our expert advisor. Any expert advisor has to decide when to enter the market and when to exit.
And the idea behind any expert advisor is what the entering and exiting conditions are.
Our expert advisor is a simple one and the idea behind it is a simple too, let’s look at it.We use two EMA indicators, the first one is the EMA of 8 days (sort EMA) and the second one is the EMA of 13 days (long EMA).
Note: using exactly these EMAs or any other thought in this lesson is not a recommendation of mine, they are for educational purpose only.
Entering (Open):
Our expert advisor will enter the market when the short EMA line crosses the long EMA line, the relative locations of the lines will determine the order type:
If the short EMA is above the long EMA we will BUY (long).
If the short EMA is below the long EMA we will SELL (short).We will open only one order at the same time.
Exiting (Close):
Our expert advisor will close the buy order when the short EMA crosses the long EMA and the short EMA ends up below the long EMA.
And will close the sell order when the short EMA crosses the long EMA and the short EMA ends up above the long EMA.Our order (buy or sell) will also be automatically closed when the Take profit or the Stop loss points of profit/loss are reached.
Modifying:
Beside entering (opening) and exiting (closing) the market (positions) our expert advisor has the ability to modify existing positions based on the idea of Trailing stop point.
We will know how we implement the idea of Trialing stop later in this lesson.
Now let’s resume our code cracking.
//---- input parameters extern double TakeProfit=350.0; extern double Lots=0.1; extern double TrailingStop=35.0;In the above lines we have asked the wizard to declare three external variables (which the user can set from the properties window of our expert advisor).
The three variables are all double data type. We have initialized them to default values (the user can change these values from the properties window, but it recommended to leave the defaults).
I have to pause again to tell you a little story about these variables.
Stop loss:
It’s a limit point you set to your order. When reached the order will be closed, this is useful to minimize your loss when the market goes against you.
Stop loss points are always set below the current asking price on a buy or above the current bid price on a sell.Trailing Stop
It’s a kind of stop loss order that is set at a percentage level below (for a long position) or above (for a short position) the market price. The price is adjusted as the price fluctuates.
We will talk about this very important concept later in this lesson.
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