In the below code ? is used. ? is going to say whether label exists on the token or not. If label exists the expression works. Here my doubt is if label is not there what the expression is going to return
level = current.TotalSupplied? - current.TotalDemanded?
if (itemDependentDemand) level = current.TotalSupplied? - current.TotalDemanded?; else level = current.TotalSupplied? - (getinput(current) / getprocessflowvar(processFlow, "DepletionUnit", current.MainToken?));
Without the question mark that code will throw an exception if the object doesn’t have a label with that label name. With the question mark it will return nullvar instead.
@Matthew Gillespie Thanks for feedback.
In your answer in the last sentence you specified as With the question mark it will return bulk car instead. What do you mean by bulk car here.
The other question is
Without question mark if it is throwing exception what is the advantage of using question mark in the above code. If the label doesn't exist then With or Without question mark if it throws exception, what is the advantage of having question mark
That was an autocomplete typo, it should have said nullvar. You can read more about the ? operator here: https://docs.flexsim.com/en/20.0/Reference/CodingInFlexSim/FlexScriptAPIReference/Tree/treenode.html#Property-labelProperties
Using the ? is supposed to keep the code from throwing an exception if the label isn't there. Where is this code from?
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