Question on ATOF

[Qonfire]

(action_tile
   "accept"						;if O.K. pressed
   (strcat						;string 'em together
     "(progn 
     [color="red"] (setq SIZ (atof (get_tile \"selections\")))"[/color]	;get list selection
     " (done_dialog)(setq userclick T))"		;close dialog, set flag
   );strcat
 );action tile

 (start_dialog)					;start dialog

 (unload_dialog dcl_id)				;unload

  (if userclick					;check O.K. was selected
   (progn

     [color="red"](setq SIZ (fix SIZ))	[/color]			;convert to integer; 
    [color="red"] (setq SIZ (nth SIZ NAMES))[/color]			;get the size

   );progn

 );if userclick

(princ)

 

Hello Tigers

 

i'm stuck here,this tutorial was taken from link below. If value in tile "selection"

is "M8", how come that atof function processes it. http://www.afralisp.net/dialog-control-language/tutorials/dialog-boxes-and-autolisp-part-2.php

[Lee Mac]

Since the 'selections' tile is a list tile, (applies to list_box / popup_list), get_tile return a string containing the zero-based index of the selected item. The author has used the atof function to convert this string to a real, then used fix to convert to an integer. If I were writing it, I would cut out the middle-man and use atoi to convert directly to an integer.

 

Lee

[Qonfire]

Thanks for reply.

get_tile returns a string containing the zero-based index of the selected item

, In the tutorial one of the element in list is "M10", (atof (of that) returns "M10"

if I plugin "m10" after couple of lines in this (setq SIZ (fix SIZ)) doesn't work.

 

atof - This function changes a string into a real number.

 

        Syntax : (atof string)

           string - any valid string.

                (atof "345") returns 345.0

                (atof "345.9") returns 345.9

                (atof 345) returns "Error: Bad Argument Type"   [345 is a number, not a string]

                (atof 345.9) returns "Error: Bad Argument Type"   [345.9 is a number, not a string]

                (atof "-345") returns -345.0

                (atof "-345.9") returns -345.9

                (atof "345JEFF49") returns 345.0

                (atof "JEFF49") returns 0.0

looked here too...

if it converts to a real number how come the output is string. I'm sure Lee answered fully covering the question...however it didn't click yet

[Lee Mac]

re-read my post - for a list tile, get_tile returns the index of the selected item.

 

Hence, if the first item is selected, get_tile returns "0", if the second, "1" etc. etc.