In yesterday’s post, I talked about three different ways to write expressions: prefix, infix, and postfix expressions. I also promised to write up a web-based example that would show the guts of each algorithm in action. Well, here it is! Use the three buttons at the top to switch between the different machines. Enter an expression in the box and click run to evaluate it. The only things that are supported at the moment are numbers (integers or floating point) and the operators +, -, *, and /, although the code is extensible enough that adding more shouldn’t be an issue.

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