Call by reference / value

[TerryRitchie]

Thing to remember is that passing via reference only works IF variable types match.  For example, change the types from DOUBLE to _FLOAT in the program above.

Best practice, if one doesn't want values to pass by reference, is just to pass to temp variables.

SUB foo(tempX, tempY)
    x = tempX: y = tempY
    'Now use x/y with zero worry over changing your original variable values.

Yep, I explain this method in Lesson 6 of the tutorial here. The code that generates Figure 7 (variablepassing2.bas) is an example of Steve's method.