InFix & PostFix notation

[SlideRule]

An edifying exposition on notation in Order of Operations and RPN (Master of Arts in Teaching (MAT) Masters Exam) by Greg Vanderbeek, University of Nebraska - Lincoln, July 2007. This academic paper encompasses history, technology, philosophy, application etc., with an emphasis on postfix (RPN) & infix (PEMDAS / BEDMAS) notations and culminates in favor of RPN with an infix to postfix conversion algorithm {& attendant flowchart} at the end.

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SlideRule

[rprosperi]

Nice paper SlideRule, thanks for sharing it.

One of the conclusions about the disadvantages of RPN calculators:

Quote:RPN calculators are comparatively expensive and rare compared to an infix calculator. When an RPN calculator is unavailable, frequent users of RPN calculators may find use of infix calculators difficult due to habit.

I wonder if the author is a member here...

[pinkman]

Really interesting, thanks for the sharing.

Like it is written, as a RPN users I don’t like infix calculators and I have trouble using them, but algebraic advanced calculators such as the Prime have a great advantage: in case of an error in a long numeric calculation you can see and correct it. In RPN I often double check the calculation.

Another con of RPN that is not mentioned in the document: it is hard to read.

[Jim Horn]

A similar flowchart was in my college computer programming textbook, albeit with a bug. When I bought my HP-67 in 1976, it was fun putting that algorithm into its 224 steps, making the HP-67 capable of handling infix calculations directly, with roughly 12 levels of parenthesis and pending operations (including CHS and exponentiation). Gene Wright put that program in his Games collection that was mentioned in this forum a year or so ago. Not a very practical program but an enjoyable exercise in parsing and stack manipulation in such a limited programming system!