Numbers and the Math library. example from a Well House Consultants training course
More on Numbers and the Math library. [link]
Source code: ccinit Module: U102
In Lua, you need to initialise variables before
you perform arithmetic on them, but you CAN test
them (and if they don't exist, they will return
The line in the function that deals with callcounter
is setting the variable to the existing value + 1 if
the variable already exists, or to (0) + 1 if it is
new - all in one line.
Note that variables not otherwise declared in Lua
are global, so that callcounter is shared between
each invocation of the function and the main code.
callcounter = (callcounter or 0 ) +1
return val * 2
rv = demo (17)
rv = demo (7)
print ("Call count is " .. callcounter)
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This module and example are covered on the following public courses:
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This example comes from our "Numbers and the Math library." training module. You'll find a description of the topic and some other closely related examples on the "Numbers and the Math library." module index page.
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