Re: Rainfall


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Posted by John Nichols on February 07, 2005 at 17:54:11 from 165.91.196.86 user Mcneacail.

In Reply to: Re: Rainfall posted by andyb on February 07, 2005 at 14:41:09:

No Jon is not making it up.

RPN or Reverse Polish Notation is a very good way to do maths on a calculator.

we can think of the expression
2+2=4.

If we input first 2 then + then 2 then = we get 4 using traditonal notation.

Or we can think in terms of list operations
(+ 2 2) has a side effect called 4. We use the enter key to create the side effect.

Their are a number of advantages to the concept of a side effect rather than just worrying about 4.

(= 4 0) has a side effect no or false.

So RPN is a way of doing this type of calculation quickly.

For those used to RPN it is twice as fast as the trad notation.

The Hewlett Packard company started selling oscilloscopes and moved onto calculators. Their calculators had names usch as HP 15C. The higher the number generally the better the calculator.

For the 1980's the best calculator in the world was the HP 41 CV.

JMN



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