1. Functions? I'm Lost!!
Could someone give me an example of how to use a function.
I just can't seem to grasp the concept. I know they return
a value. I just can't find an example where anything for the
function is used any where else in the program. I'm just lost.
Thanks for your time.
Dave
2. Re: Functions? I'm Lost!!
On 17 May 2000, at 17:20, David Roach wrote:
Date sent: Wed, 17 May 2000 17:20:58 -0400
Send reply to: Euphoria Programming for MS-DOS <EUPHORIA at
LISTSERV.MUOHIO.EDU>
From: David Roach <roachd_76 at YAHOO.COM>
Subject: Functions? I'm Lost!!
To: EUPHORIA at LISTSERV.MUOHIO.EDU
> Could someone give me an example of how to use a function.
> I just can't seem to grasp the concept. I know they return
> a value. I just can't find an example where anything for the
> function is used any where else in the program. I'm just lost.
>From the Eu help files:
functions
These are just like procedures, but they return a value, and can be used
in an expression, e.g.
function max(atom a, atom b)
if a >= b then
return a
else
return b
end if
end function
Any Euphoria object can be returned. You can, in effect, have multiple
return values, by returning a sequence of objects. e.g.
return {x_pos, y_pos}
We will use the general term "subroutine", or simply "routine" when a
remark is applicable to both procedures and functions.
3. Re: Functions? I'm Lost!!
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Hi Dave,
Most libs use functions to return a value to the calling program, =
since they can't directly put a value to the program variables.
IE. David Cuny's winlib..
when you create a control( a window or listbox or whatever), it =
returns a handle so you can access the control you created later.
example..
<CODE>
include win32lib.ew
constant
=
,0),
-- ^^ this is a function. it returns a handle so winlib =
can manipulate it in later code
Mnu_File=3Dcreate(Menu,"&File", Win_Main,0,1,0,0,0),
-- ^^ the value returned by create..... ^^ this is the handle return =
by creating the window
Mnu_Fexit=3Dcreate(MenuItem,"E&xit",Mnu_File,0,0,0,0,0)
-------------------------------------------------------------------------=
-----
--EVENTS
procedure onMnu_Fexit()
closeWindow(Win_Main)
end procedure
-------------------------------------------------------------------------=
-----
--EVENTS
onClick [Mnu_Fexit] =3D routine_id("onMnu_Fexit")
-- ^^ this is a function too..
WinMain(Win_Main, Normal)
</CODE>
Chris
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.2314.1000" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">Hi Dave,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"> =
Most libs use=20
functions to return a value to the calling program, since they can't =
directly=20
put a value to the program variables.</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">IE. David Cuny's =
winlib..</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"> =
when you create=20
a control( a window or listbox or whatever), it returns a handle so you =
can=20
access the control you created later.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">example..</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"></FONT> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans =
MS"><CODE></FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"></FONT> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">include =
win32lib.ew</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans =
MS">constant<BR> =20
; =20
-- ^^ this is a function. it returns a handle so winlib can manipulate =
it in=20
later code</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"> =20
Mnu_File=3Dcreate(Menu,"&File", Win_Main,0,1,0,0,0),</FONT></DIV>
<DIV><FONT color=3D#0000ff=20
face=3D"Comic Sans MS"> -- ^^ the value =
returned by=20
create..... ^^ this is the handle return by creating the=20
window<BR> =20
NT=20
color=3D#0000ff=20
face=3D"Comic Sans =
MS">---------------------------------------------------------------------=
---------<BR>--EVENTS</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">procedure=20
onMnu_Fexit()<BR> closeWindow(Win_Main)<BR>end=20
procedure</FONT></DIV>
<DIV><FONT color=3D#0000ff=20
face=3D"Comic Sans =
MS">---------------------------------------------------------------------=
---------<BR>--EVENTS</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">onClick [Mnu_Fexit] =
=3D=20
routine_id("onMnu_Fexit")</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"> =20
=
=20
-- ^^ this is=20
a function too..<BR></DIV></FONT><FONT color=3D#0000ff=20
face=3D"Comic Sans MS"></FONT>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS">WinMain(Win_Main,=20
Normal)</FONT></DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans MS"></FONT> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans =
MS"></CODE></FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#0000ff face=3D"Comic Sans =
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4. Re: Functions? I'm Lost!!
I guess I'm just confused on where and how to use them. I understand that
they return a value. ex.
function same(object a, object b)
return not compare(a,b)
end function
I understand that this will return a value of 1 if true and a value 0 if
false(I believe). I have tried to use them and often get errors. Is there
anywhere that tells where and under what secumstances you can call a
function. I can only get them to work in an if...then statement. Are you
supposed to be able to use them anywhere else? Have I just missed something?
Or is that the only time you would actually need to use a function? I'm just
new and get confused, that's all.
Just a note:
This forum is great. I always get help with the problems that I have.
If it weren't for ya'll I'd have given up a long time ago. Thanks Bunches!!
Dave
5. Re: Functions? I'm Lost!!
On Wed, 17 May 2000 17:20:58 -0400, David Roach <roachd_76 at YAHOO.COM> wrote:
>Could someone give me an example of how to use a function.
>I just can't seem to grasp the concept. I know they return
>a value. I just can't find an example where anything for the
>function is used any where else in the program. I'm just lost.
>Thanks for your time.
>
>
>Dave
Dave:
Here is a simple example
-- Say I want to create a function that adds 2 numbers
function sum( atom no1, atom no2 )
return no1 + no2
end function
-- to call the function and print the sum of 2 numbers
? sum( 15, 20 )
-- we could just write this
? 15+20
-- but the purpose of function ( which can be very complex ) is
-- to be defined only ONCE in your program and be called through out
-- your program to perform the task over and over again and return a
-- VALUE. Remember the big different is that a VALUE is return in a
-- function and NO VALUE is return from a procedure.
Bernie
6. Re: Functions? I'm Lost!!
--Here's a function:
function foo( atom a, atom b)
return (a+b)
end function
--Here's how it's used.
atom a
a=foo(2,2) -- the function call
?(a)
a=foo(2,3)
?(a)
?(foo(3,3))
--A function returns a value, so it needs to have someplace for the value to
;
--A procedure doesn't return a value, it just does something
procedure printboo(atom number)
for i = 1 to number do
puts(1, "Boo")
end for
end procedure
printboo(3)
printboo(4)
printboo(5)
Bye
Martin
----- Original Message -----
From: David Roach <roachd_76 at YAHOO.COM>
To: <EUPHORIA at LISTSERV.MUOHIO.EDU>
Sent: Wednesday, May 17, 2000 2:20 PM
Subject: Functions? I'm Lost!!
> Could someone give me an example of how to use a function.
> I just can't seem to grasp the concept. I know they return
> a value. I just can't find an example where anything for the
> function is used any where else in the program. I'm just lost.
> Thanks for your time.
>
>
> Dave
>
7. Re: Functions? I'm Lost!!
The following code defines a function that returns the number 5 and uses
it:
integer a -- Define an integer named "a"
function return5() -- Define the function "return5"
return 5 -- Return 5
end function
a=return5() -- Get return5() to return its value and assign it to "a"
? a -- Print the integer "a", just to test it out
The following code defines a function that returns the absolute value of a
number and uses it:
function abs(atom number) -- Defines abs().
return sqrt( number * number ) -- Behold the magic formula!
end function
? abs(-54) -- Should say 54
