Use of Functions

[SMcNeill]

SUBS *do* something.   FUNCTIONS *return* something.     <--That's the difference between the two.

CLS, PRINT, BEEP, and SLEEP all *do* something for you; they're all SUBS.  CLS will clear the screen.  PRINT will print something to the screen.  BEEP makes your wife go crazy at 2 AM. SLEEP, contrary to the name doesn't help you cure insomnia....

On the other hand, COS, ABS, INT, and RND are all FUNCTIONS, as they return *something* to us.  COS returns the cosine value of the angle we give it.   ABS returns the absolute value of a number.  INT tells you what someone's  IQ is, and RND is good for random pickup lines at a bar..   (Or something like that.  )

To use a function, you need two basic things:

1) To give the function a NAME
2) To assign a value to that function's NAME before exiting the function

FUNCTION foo&
    foo& = 3
END FUNCTION

Function Steve$
  Steve$ = "Steve is Awesome"
END FUNCTION

Notice that the function name is important in marking what TYPE of return value we want.  foo& is a LONG.  Steve$ is a STRING.  It's that simple to make your function.

Parameters are simply passed so that you can do something more useful than what I'm doing above with those pitiful functions. 

Function AddString$ (first$, second$)
   AddString$ =  first$ + " " + second$
End Function

And then to make use of it is to either assign it to a return value, or else use it as an operation for a SUB.

MyName$ = AddString$("Steve","McNeill")
PRINT MyName$

Or just: PRINT  AddString$("Steve","McNeill")

The first MyName$ is assigning the return to the variable MyName$.  The second is sending it to a SUB to do something directly.  (Print, in this case.)


That's all there is to it.  Nothing complex or complicated to see here.