Hi,
this might be a stupid question, but here it goes:

i am trying to increment a value while a given expression is false.
used to just saying something like i++ for that, but i don't know the language sMath is based on.

i am getting an error :"output value must be defined for the called procedure"
the example is attached.

ty for you're help.

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Hi, this discussion about "local variables and functions" might be of help
http://en.smath.info/forum/yaf_postsm5930_Functions-behave-differently-in-0-9.aspx#post5930

Edit:
just put b.wall after the while loop