optional-parametersdosboxqbasicquickbasic

QuickBasic optional arguments

Is it possible to write a subroutine or function with optional arguments?

for example: MyFunct (x AS INTEGER, [y AS INTEGER, Z AS INTEGER]) so that I can use the function with only the first argument and sometimes with all arguments, in the same program, like the following for example: Myfunct 5 MyFunct 5,6,7

Also, is it possible to write a sub or a function that takes arguments in format that is used with some of the graphics commands in QuickBasic, like the WINDOW and LINE.. For example: WINDOW (10,50)-(100,100) LINE (10,10)-(50,50

I tried using square brackets, [], because the manual said those represent the optional arguments, but I guess it is only for reading the syntax conventions. Is there any way to have optional arguments?

Solution

  • So, the way I would do it would be to pass your arguments in a string, separated by some delimiter. Then you can break the variables out of the string once in the function with logic to handle if the argument is missing.

    MyFunc (“x=1,y=2,z=3”)

    String parser left as an exercise for the OP