advantages of RPN

[Alvaro]

(05-23-2014 04:35 PM)Matt Agajanian Wrote:  While we're on the subject, (RPN of course), I found a very helpful iPhone app that makes for quite a good tutorial and understanding of RPN if one was ever to teach others about RPN. It's called 'Active RPN.'

What makes this app so helpful;

T, Z, Y and X are always visible and in top-to-botttom order so users can see stack behaviour
Last X is also visible and, unique to this app, Last Y is shown, retained and can be recalled.
An ongoing trace mode and page are available.

Here's the webage link:

http://www.math3g.com/Site/RPN_Progs.html

Here's the iPhone app link:

https://itunes.apple.com/us/app/active-r...47341?mt=8

That with the "Stack" and Variables is one thing that I never could understand, it sounds to me as "joke".
The usage of a Variable on a Program is that it can be used many times. That is the sense of Variables. And NOT only at a Stage of program but ANYTIME you need.
I realy don´t understand the sense of that "Stack operations" DROP, DUP .