(princ "\nPoint #2") I don't understand why it is printed twice.

[Anonymous]

Hi, guys!

Please help me to understand the logic of (princ)

This is the program I have

+++++++++++
(defun c:PrintTest()
;(setq p2 3)
; (princ)

(princ "\nPoint #2") ;(princ p2)

;(princ (strcat "\nPoint #2 " (rtos (car p2) 2) "," (rtos (cadr p2) 2) "," (rtos (last p2) 2)))

)

+++++++++++++++

I pasted it "as is" without removing comments.

++++++++++++
When I run program, I get the following result:

Command: PRINTTEST
Point #2"\nPoint #2

++++++++++++

I don't understand why it is printed twice.

Thanks!

[ВeekeeCZ]

Since you have replied here I guess you do understand now.

In case you're not see the help.

Especially this part: ...

Return Values

Type: Integer, Real, String, List, Symbol, File, Ename (entity name), T, or nil

The value of the evaluated expr. If called with no arguments, princ returns a null symbol.

The red part is why it is twice. The blue one why we put (princ) at the and to avoid previous.

[Anonymous]

Thanks for reply! 

Now, I know how to fix this situation,

but I don't understand why it works

The first (princ "\nPoint #2") returns vallue,

the second (princ) returns null

So, I don't understand why second null prevent returning value of the the first princ?

Thanks!

[ВeekeeCZ · Accepted solution]

---

@Anonymous wrote:

Thanks for reply! 

Now, I know how to fix this situation,

but I don't understand why it works

The first (princ "\nPoint #2") returns vallue,

the second (princ) returns null

So, I don't understand why second null prevent returning value of the the first princ?

Thanks!

---

It's not. In command line you can see just last one. 

Try to write into command line this:

(setq a 1)

then !a to get value of a

Then (setq b 1)(princ)

try !b

So see help what setq returns. If you put (princ) right behind... you'll see nothing. But it's still there. You can catch it with 

(setq d (setq c 2))(princ)

then if you type !d it returns same value as !c which is 2.

[Anonymous]

It's not. In command line you can see just last one. 

Yes, this explain the issue!
thanks!