MQL4 TUTORIAL BASICS – 52 SIMPLE EXTERNAL CANDLE NUMBER

In this video, we are going to create an expert advisor that is able to calculate a simple moving average based on an external variable for the number of candles. In this case, we are using one hundred candles to calculate the moving average, so let’s find out how to do that with mql4.
To get started please click on the little icon here or press F4 on your keyboard, now you should see the Metaeditor window and here you want to click on file, new file, expert advisor from template, continue, I will call this file simple external candle number, click on continue, continue and finish.
Now you can delete everything above the on tick function and the two comment lines here, we start by creating an external integer value called number of candles.
The first value will be one, we will change that later and the modifier extern is used to create something that can be adjusted without the need to change the source code.
Inside of the on tick function we start by creating a string variable for the signal, we don’t assign any value here because this is going to be calculated later.
To calculate the moving average we use the integrated ima function for the current symbol on the chart and the currently selected period on that chart.
We want to calculate it for the number of candles that we will define, this parameter and the last one have the value zero because we don’t want to use any shift values. This one is mode underscore sma – all in capital letters – that stands for simple moving average, we are going to calculate the result based on the close price and if the moving average value is below the current close price that would be a buy signal so we assign the word buy to our signal.
Otherwise, if the moving average value is bigger than the current close price that would be a sell signal and now we assign the word sell to our signal.
And when the signal is buy and orders total has a return value of zero, or in other words, we have no open orders that’s when we use order send to buy ten micro lot.
Otherwise, if the signal equals sell and we have no open orders that’s when we use order send to sell ten micro lot.
Finally, we use the comment function to create an output on the chart, it will output the number of candles is, followed by the calculated value for the number of candles.
In a new row, we want to see the current signal is followed by the calculated signal and below we also want to output a hint: Please also adjust the number of candles on the chart!
And that’s about it.
Well if this is too fast for you or if you don’t understand what all the code here does maybe you want to watch one of the other videos in this basic series first or maybe even the premium course on our website might be interesting for you, for now, please click on the compile button or press F7 on your keyboard that should work without any errors and if that is the case you can click on a little button here or press F4 to go back to Metatrader.
And in Metatrader we want to pick a chart without any indicators and click on insert, indicators, trend, moving average, we will start with a value of one hundred candles, we use a simple moving average that is based on the close price, so let’s pick a color and click on ok. Here is the sma, now we use a right mouse click, select template, save template and save it as tester dot tpl because this is the template that we are going to see in the next strategy test, so let’s click on save, you can override the old value and now click on view, strategy tester or press control and r, please pick the new file simple external candle number dot ex4, mark the visual mode here and start a test.
Here is our little expert advisor at work, this is the moving average that is based on one hundred candles, it matches the number that we see here, so you should see buy and sell signals based on this value here and here we have a sell signal, so our little expert advisor is working.
Let’s stop the test here, select expert properties, I would now like to calculate the value for fourteen candles, let’s click on ok, we need to change the expert advisor properties, pick a new color, click on ok, here is the new moving average value so let’s right-click, select template, save template and save the new value as tester dot tpl again and afterwards we start a new test.
This is the same expert advisor but now it’s calculated based on fourteen candles, our little expert advisor is working as expected and in this little video you have learned how to create an expert advisor that is able to trade a simple moving average and you can change the values without modifying the source code by just adjusting the expert properties and you have coded the whole thing with a few lines of mql4 code.

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