Lisp for calculations

[viviancarvalho]

I am finding difficulty in getting this well done. It does gives me the end result of the calculation but not in the way i actually want.

Please help.

 

(defun c:cf(/ sm,cfm,q)

(setq sm (getreal "\n PLEASE ENTER AREA IN SQ.MT : ")

q (getreal "\n PLEASE ENTER THE REF FACTOR : ")

cfm (getreal(* q(* 10.76 sm))))

(alert"THE REQUIRED CFM FOR THIS AREA IS" cfm))

[MSasu]

Please take care that the GETREAL statement don’t accept another AutoLISP function as argument; however you can discontinue it’s usage since the result of the calculation is already a real number.

 

And ALERT accept only one argument, so you need to concatenate the string - don't forget to convert the number:

 

(alert (strcat "THE REQUIRED CFM FOR THIS AREA IS: " (rtos cfm)))

 

Regards,

[viviancarvalho]

Thanks for that. It made my life more easier

[MSasu]

You are welcomed!

 

Reading again my post just realizes that I wasn’t just right: the GETREAL statement will not accept an AutoLISP expression as response; however you may use an expression to construct the prompter:

 

(getreal (strcat "Input the length <" (rtos Var 2 2) ">: "))

 

Sorry for inconvenience!

Regards,

[MSasu]

Another issue that missed first time – the separator for local variables should be space not comma (even if this doesn’t raise a fatal error):

 

Wrong syntax:

defun c:cf(/ sm,cfm,q

 

Right syntax:

defun c:cf(/ sm fm q)

 

Regards,

[viviancarvalho]

Yes i got it at ur first reply itself.

thanks again.

[alanjt]

You should look into cond, and, if statement use to trap errors. If you don't enter a value for SM or Q, the routine will error.

 

(defun c:CF (/ SM Q)
 (and (setq SM (getreal "\nArea in Sq. Mt: "))
      (setq Q (getreal "\nRef. Factor: "))
      (alert (strcat "Required CFM for area: " (rtos (* Q (* 10.76 SM)))))
 ) ;_ and
 (princ)
) ;_ defun