Just wondering, what does "data_stream" do in a function constructor?

At first, if not filled, by default it is overrided to 0. I thought it that means using BarsOfData(1) data as input of calculating the function, so I thought if I pass in 1, then it would calculate using BarsOfData(2) as input.

But it turned out it does not behave that way. But after some trial and error, I still could not find out what it means.

 

Code

public DirMovement(CStudyControl _master) : this(_master, 0) {} public DirMovement(CStudyControl _master, int _data_stream) : base(_master, _data_stream) { }

Hi sorry, I found out the answer is that if I would like to use 2nd Bar data, I should fill in 2, not 1.