Java String manipulation (A/B)+C

Question

Hello,

is there any java library in the wild which can "calculate" string:

(aaa/bbb/ccc)+ddd

into

aaa ddd, bbb ddd, ccc ddd

and can maybe "solve" nested:

(a+(b/c))/((d/e)+f)

to

a b, a c, d f, e f

Thanks

Answer 1

I dont know of any off hand, but I would go ahead and just write the code off hand. Parse the file, find (), Split strings by /, at the end add all / strings with the + string, and it should work out.

Answer 2

Try a parser generator for Java such as Jack or one of the others. Parsers are a great tool in a programmer's repertoire, and those tools make them fairly easy.

Answer 3

I know a open source math parser from mycsharp.de which got quite good feedback, its C# but might be a good example how to go (and easy to convert). Sadly, its not only C# but german.

But there are many math parser out there, just google "math expression parser" or something like that. Have a look at lex, too!

Answer 4

I assume you are trying to solve a equation. Then you can do this:

1. Use regex to split the equation or split the string to create an array of individual chars.

2. Use a LinkedList in Java to construct the List, follow BODMAS: search, solve and remove.

Example: 2-3+1

Regex gives: [2, -, 3, +, 1]

Insert it into a LinkedList and first search for (), then +..etc (follow BODMAS). So when + is encountered, do: -3+1, remove + and 1. Replace 3 with the sum (2).