Exp4j

exp4j is a small Java library for evaluation of mathematical expressions. It implements Dijkstra's Shunting-yard algorithm to translate expressions from infix notation to Reverse Polish notation and calculates the result using a simple Stack algorithm.

exp4j

Stable release	0.4.3 / 2014-10-10
Written in	Java
Type	Math
License	Apache License 2.0
Website	www.objecthunter.net/exp4j/

Features

• Variables can be used in expressions
• exp4j comes with a set of common built-in functions
• Users can create and use their own custom operators
• Users can create and use their own custom functions

License terms

exp4j is released under the terms of the Apache License 2.0

Examples of usage

Calculating the result of $3*{\frac {\sin {(\pi )}-2}{e}}$ can be done in the following way: <syntaxhighlight lang="java"> Expression e = new ExpressionBuilder("3 * (sin(pi) - 2 )/ e")

       .variables("pi", "e")
       .build()
       .setVariable("pi", Math.PI)
       .setVariable("e", Math.E);

double result = e.evaluate(); </syntaxhighlight>

See also

• mXparser - Mathematical Expressions Parser / Evaluator