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Posted By: artie505 Any HP calculator fans? - 09/01/17 04:49 AM
I found nonpareil for OS X (simulator of hp-11c, hp-12c, hp-15c, hp-16c, hp-35, hp-45, hp-55, hp-80, hp-21, hp-25c, hp-32e, hp-33c, hp-34c, hp-37e, hp-38c & hp-38e calculators).
Posted By: grelber Re: Any HP calculator fans? - 09/01/17 07:47 AM
Loved the calculators. Hated reverse Polish notation.
(We're talking about life in the '70s. Don't know what HP's been up to since.)
Posted By: Ira L Re: Any HP calculator fans? - 09/01/17 04:08 PM
I agree with you on RPN.

In some of the classes I taught, students were required to have a calculator with statistical capabilities. I would always advise them to avoid HP/RPN. Over the years students did show up with HP calculators that were algebraic, non-RPN, so the company may have moved into this more "standard" entry scheme.
Posted By: Virtual1 Re: Any HP calculator fans? - 09/01/17 06:47 PM
Originally Posted By: grelber
Loved the calculators. Hated reverse Polish notation.
(We're talking about life in the '70s. Don't know what HP's been up to since.)

Well there are times where you either have RPN or a crapton of parentheses. And when parens get buried 4+ levels deep it starts getting really tricky seeing what the actual order of operations is going to be.
Posted By: ryck Re: Any HP calculator fans? - 09/01/17 07:20 PM
Originally Posted By: grelber
Loved the calculators. Hated reverse Polish notation.

Originally Posted By: Ira L
I agree with you on RPN.

Originally Posted By: Virtual1
Well there are times where you either have RPN or a crapton of parentheses.

Okay, oaky...I'll be the one to put up his hand and ask "What is Reverse Polish Notation?" I'm assuming it isn't asableik egasuas.
Posted By: grelber Re: Any HP calculator fans? - 09/01/17 07:50 PM
Originally Posted By: ryck
Okay, [okay] ... I'll be the one to put up his hand and ask "What is Reverse Polish Notation?"

As Pan Wiki says:
"Reverse Polish notation (RPN), also known as Polish postfix notation or simply postfix notation, is a mathematical notation in which operators follow their operands, in contrast to Polish notation (PN), in which operators precede their operands."
https://en.wikipedia.org/wiki/Reverse_Polish_notation

Mmmmm ... kielbasa tongue
Posted By: artie505 Re: Any HP calculator fans? - 09/01/17 09:06 PM
Originally Posted By: Virtual1
...when parens get buried 4+ levels deep it starts getting really tricky seeing what the actual order of operations is going to be.

Yep!

Although at first glance, I can see where RPN takes an awful lot of getting used to...reading it more-so than writing it.
Posted By: Ira L Re: Any HP calculator fans? - 09/02/17 02:06 PM
Originally Posted By: grelber
Originally Posted By: ryck
Okay, [okay] ... I'll be the one to put up his hand and ask "What is Reverse Polish Notation?"

As Pan Wiki says:
"Reverse Polish notation (RPN), also known as Polish postfix notation or simply postfix notation, is a mathematical notation in which operators follow their operands, in contrast to Polish notation (PN), in which operators precede their operands."
https://en.wikipedia.org/wiki/Reverse_Polish_notation

Mmmmm ... kielbasa tongue


That is to say, with RPN you evaluate expressions using correct mathematical order of operations AND enter the expressions into the calculator in that order.

With "regular" calculators, you still evaluate mathematically, but enter the expressions as you would write them on a piece of paper.

For example: 2 x (3+4). This is 14. "Regular" entry is 2, x, (,3,+,4,) [no commas, just used here to typographically separate the keystrokes].
In RPN, you would enter [let's see if I remember correctly] (,3,+,4,),x,2.

Whew. smirk
Posted By: joemikeb Re: Any HP calculator fans? - 09/02/17 05:56 PM
Originally Posted By: Ira L
For example: 2 x (3+4). This is 14. "Regular" entry is 2, x, (,3,+,4,) [no commas, just used here to typographically separate the keystrokes].
In RPN, you would enter [let's see if I remember correctly] (,3,+,4,),x,2.

My recollection using RPN on an HP calculator the actual keystrokes would be
3 enter 4 + 2 x
Posted By: artie505 Re: Any HP calculator fans? - 09/02/17 08:48 PM
Following grelber's linked Wikipedia article, 2 x (3+4) would be written in RPN as either 3 4 + 2 x or 2 3 4 + x .

More: I'm not sure at which points you'd hit enter.
Posted By: Ira L Re: Any HP calculator fans? - 09/04/17 02:45 PM
Yeah, the operation does come after the digit. Don't recall where "enter" occurs.

I'm glad we are all so up on RPN! crazy
Posted By: Virtual1 Re: Any HP calculator fans? - 09/05/17 01:28 PM
seeing as the operators are entered last, technically you shouldn't need to tell it to calculate the line because it already knows its time. Each time you hit an operator, it knows the operand(s) have already been provided and it can perform the operation immediately. Hitting "=" or "enter" should be implied. Unless you have a calculator that lets you edit before calculating anyway.
3,4+2* (3,4+ immediately evaluates to 7, and then 2* immediately evaluates to 14)
2,3,4+* (2,3,4+ causes 3,4+ to immediately evaluate to 7 and leaves 2,7 in the stack, then when you hit * it evaluates to 14)

This is processing a stack btw. A stack is like a stack of dinner dishes, you can only add a plate on the top ("push") or take a plate off the top ("pop") a stack. When you enter a number, it's pushed onto the stack. When you enter an operator, it pops however many operands the operator needs (usually 2, sometimes 1 or 3) and evaluates them, and pushes the result back onto the stack. Operators like !, sin, and Log would only pop one operand and push the result into its place.

Stacks and Queues are both interesting structures in programming. Circular queues can really get weird but can be very useful. None of them behave well when they overflow.

Posted By: joemikeb Re: Any HP calculator fans? - 09/05/17 09:29 PM
Originally Posted By: joemikeb
My recollection using RPN on an HP calculator the actual keystrokes would be
3 enter 4 + 2 x

Explanation:
  • The reason for pressing "enter" between the 3 and the 4 is to tell the computer that 3 is one entry on the stack and 4 another.
  • The + operator following the 4 serves the same purpose as well as signaling an add operation.
  • Since an operation has been performed the 2 is the taken as a new data entry on the stack and like the 4 is terminated by the x operator (x).

2 enter 3 enter 4 + x would also work, but it takes an additional keystroke and to me is less intuitive than the first version.
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