Expert Advisor Programming by Andrew R. Young

EXPERT ADVISOR PROGRAMMING
double iMA(string Symbol, int Timeframe, int MAPeriod, int MAShift, int MAMethod,
int MAPrice, int Shift)
• Symbol – The symbol of the chart to apply the moving average to.
• Timeframe – The time period of the chart to apply the moving average to.
Every indicator function in MQL starts off with these two parameters. After this are the indicatorspecific
parameters. These correspond to the contents of the Parameters tab in the Indicator
properties.
• MAPeriod – The look-back period of the moving average.
Almost every indicator has at least one period parameter. Most indicators are calculated using a price
series taken from the previous bars. For example, a period setting of 10 would mean that the
indicator uses price data from the last ten bars to calculate the indicator value.
• MAShift – The forward shift of the moving average line, in bars. This is different than the
Shift parameter below.
• MAMethod – The calculation method of the moving average. Choices include simple,
exponential, smoothed or linear weighted.
Any indicator that uses a moving average may give you the option to choose the MA calculation
method. We'll talk about moving average methods later in the chapter.
• MAPrice – The price array to use when calculating the moving average.
This can be the close, open, high, low or some type of average; such as median, typical or weighted
prices. We'll discuss applied price constants later in the chapter.
• Shift – The backward shift of the bar to return the calculation for.
The Shift parameter is the final parameter in any indicator function. This is the index of the bar to
return the indicator value for. A value of 0 returns the indicator value for the current bar. A value of 3
will return the indicator value from 3 bars ago.
The moving average and similar indicators are drawn directly on the chart. You can create trade
conditions based on the relationship between indicators and price. Our moving average cross is an
example of a price relationship between two indicators. When one indicator's price is greater than the
other, a buy or sell signal is generated.
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