CTL trading: Learning MT4 MQL : First simple MA strategy

This post will show how you can make an extremely simple MT4 Expert Advisor (EA). So the purpose is not to make a strategy that is profitable. No the purpose is to make something as simple as possible so we will be able to understand the code. I advice everybody that wants to learn to make his own EA in MT4 MQL to start with basic and very simple code.

We are going to make a simple moving average strategy.

Buy with stop loss (S/L) and profit target (T/P) when currency is going above the moving average exponential

Sell with stop loss (S/L) and profit target(T/P) when currency is going below the moving average exponential

Lets write the strategy and explain all parts. The explanation is between // and //. In the strategy you write you can uses // for adding explanations.

//All the values that the user of the EA should be able to change are declared first with extern //

//int = integer because TakeProfit and StopLoss are rounded numbers//

//use double if you want to use values like 400.50 or 200.10//

extern int TakeProfit = 400;

extern int StopLoss = 200;

//Position is an integer value that we are going to use to determine if we have an open position //

//Position 0 means no open position//

//Position 1 means 1 open position and its a long//

//Position -1 means 1 open position and its a short//

int Position = 0;

//Next part is a function. The name of the function is CalcPosition. Void is used for functions that don't//

//return a value. This function will fill the variable Position that we declared above. //

//Position will be 0 for no position, position will be 1 if we have an open long and -1 if we have an//

//open short. The function will be executed when we call for it in the actual program//

void CalcPosition() {

Position = 0;

for (int i = 0; i < OrdersTotal(); i++) {

OrderSelect(i, SELECT_BY_POS, MODE_TRADES);

if( OrderSymbol() == Symbol() ) {

if (OrderType() == OP_BUY) Position += 1;

if (OrderType() == OP_SELL) Position -=1;

}

//Next we start the actuel program. This always starts with int start()//

int start()

{

//Next we declare the variables that the strategy will use, variables not meant to be changed by//

//the person who is going to use the EA//

double lots, ma1, stop, profit, slippage;

//Next we fill all these variables, one by one//

lots = 0.1;

slippage = 3;

ma1 = iMA(NULL,0,21,0,MODE_EMA,PRICE_WEIGHTED,0);

stop = StopLoss*Point;

profit = TakeProfit*Point;

//With the line below we are asking that our function is executed and that the value of position is detemined//

CalcPosition();

//Next step we check if the bar is closing above the exponential moving average and we check that //

//we don't have an open position yet//

if(Close[0]>ma1&&Position==0)

{

//if that is the case the following code buys lots and puts a profit taking level above and a stop order below//

OrderSend(Symbol(), OP_BUY, lots, Ask, slippage, Ask-stop, Ask+profit, 0);

}

//Same when bar closes below EMA, if below and no open order we sell and put a profit taking level and//

//a stop loss order//

if(Close[0]<ma1&&Position==0)

{

OrderSend(Symbol(), OP_SELL, lots, Bid, slippage, Bid+stop, Bid-profit, 0);

}

//Next line just means we are going back to the beginning of the actual program//

return(0);

}

The code without all these explanations:

//-------------------------------------------------------------------------------------------//