I want to calculate the sum of part of an array of x number of periods. MathSum seemed to be what I was looking for, but while it appears in online documentation, it does not appear to be in MetaTrader 5 or the local reference (Help>MQL5 Reference).
Is there another function? Or am I just going to have to write my own?
MathSum() is a function from Standard library, you need to add this include in your code to use it :