What is Reverse Polish notation (RPN) or postfix notation?
Reverse Polish Notation (RPN), otherwise known as postfix notation, is a manner of representing and processing mathematical formulas, that is different from the algebraic notation with which most people are familiar. It is best known as the mode in which most calculators made by Hewlett Packard operate, which is very different from how nearly all other calculators work. There are also a few programming languages, such as Forth and PostScript, which use RPN. We usually think of simple mathematical operations in algebraic or infix notation. For example, if we are thinking of adding the numbers two and five together, we might write it like this: 2 + 5 In performing this operation on most calculators, you would key in the following… 2+5= … and the calculator would then display the result, 7. In RPN, we would write this same operation this way… 2 5 + …and understand it to mean that the + operator takes the two numbers that precede it, and adds them together. This seems rather weird to a hum
