Topic: IF statement error

[MeasureUp]

Could anyone give me a help for the code below?

Code: [Select]

(defun c:test ()
(setq A (getreal "\nEnter a number: "))
(setq B (getreal (strcat "\nEnter a number "
                         (progn (if (<= A 100) "(<= 50): ")
(if (> A 100) "(> 50): ")))))
)
If A = 150, it will give the user "Enter a number (> 50): "
If A = 10, it will give the user "; error: bad argument type: stringp nil"

What is wrong it gives an error message when A < 100?
Thanks for your help.

[Tharwat]

Maybe this ...

Code - Auto/Visual Lisp: [Select]

1. (and (setq A (getreal "\nEnter a number : "))
2.          (setq B (getreal (strcat "\nEnter a number "
3.                                   (cond ((<= A 100.) "(<= 50): ")
4.                                         ((> A 100.) "(> 50): ")
5.                                   )
6.                           )
7.                  )
8.          )
9.     )
10.  

[Lee Mac]

There is no need for the second condition: 'A' will either be less than or equal to 100, or greater than 100.

Code - Auto/Visual Lisp: [Select]

1. (defun c:test ( / A B )
2.     (if
3.         (and
4.             (setq A (getreal "\nEnter a number: "))
5.             (setq B (getreal (strcat "\nEnter a number (" (if (<= A 100) "<=" ">") " 50): ")))
6.         )
7.         ...
8.     )
9. )

[MeasureUp]

Thanks to Tharwat & Lee again.
A "cond" statement definitely works.

And if comparing Lee's code:

Code: [Select]

(if (<= A 100)
; do this
; otherwise do that.
); end if
with the one simplified from my code:

Code: [Select]

(if (<= A 100)
; do this
); end if
(if (> A 100)
; do that
); end ifBoth of 2 codes should work logically.
Why my code in post #1 doesn't work properly?
I want to learn from this.
Thanks.

[CAB]

Because progn returns the last value

Code - Auto/Visual Lisp: [Select]

1. (progn
2.   (if (<= A 100) "(<= 50): ") ; <---<<<  this value is never returned
3.   (if (> A 100) "(> 50): ")   ; <----<<<  when this is nil this is the value returned.
4. )