Optional and by-reference parameters in Igor Pro

Igor has no overloading; optional parameters and by-reference outputs do that work.

Function Stats(WAVE w, Variable &mean, Variable &sd)
    WaveStats/Q w
    mean = V_avg
    sd = V_sdev
End

Function Report(WAVE w, [String title])
    if (ParamIsDefault(title))
        title = NameOfWave(w)
    endif

    Variable mean, sd
    Stats(w, mean, sd)
    Printf "%s: %g +/- %g\r", title, mean, sd
End

How it works

1. Parameters in square brackets are optional; ParamIsDefault tells you.
2. An & parameter is passed by reference, so the function can write to it.
3. That is how one call returns several numbers.

Keywords and builtins used here

• End
• Function
• NameOfWave
• ParamIsDefault
• Printf
• String
• Variable
• WAVE
• WaveStats
• endif
• if
• mean

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Step 3 of 3 in Variables & functions, step 7 of 18 in Language basics.

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