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A powerful function parser

, 22 Feb 2000 123.4K 1.9K 57
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A simple yet powerful function parser that parses and evaluates standard mathematical functions
  • Download source files - 82 Kb
  • The inspiration to write this code was to have an easy-to-use parser for functions given as string. You have a string like "cos(x)-7*x/(1+x)", and you want to compute some values, maybe for displaying the graph of the function. You can write code like this:

    CFunction<long double>* fkt = CFunction<long double>::Parse("cos(x)-7*x/(1+x)");
    long double y = fkt->Execute(1.5);

    There are lots of definitions in the background, but the result is easy and fast! There is a one-time pasing step to construct the function tree, and function evaluations are only calls of standard math functions like sin, +, *, sqrt. When you want to know details about the implementaion, you should look into the source code. It would be too complex to describe the parsing algorithm here.

    License

    This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

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    About the Author

    Andreas Jäger
    Web Developer
    Germany Germany
    No Biography provided

    Comments and Discussions

     
    GeneralTo B.Starks, W.Dean, & J.Andreas Pin
    Amit Gefen8-Nov-01 13:43
    memberAmit Gefen8-Nov-01 13:43 
    GeneralOperators/precedence/types etc Pin
    Andrew Phillips26-Sep-01 19:04
    memberAndrew Phillips26-Sep-01 19:04 
    GeneralVery good success with this Pin
    Jeff12-May-01 9:59
    memberJeff12-May-01 9:59 
    GeneralYou must read jeff's reply..!! then you will success Pin
    JsSong25-Mar-02 15:47
    memberJsSong25-Mar-02 15:47 
    GeneralBugs etc below should be renamed to Dean Wyant knows little about programming. Pin
    B. Starks13-Apr-01 8:36
    memberB. Starks13-Apr-01 8:36 
    GeneralRe: Bugs etc below should be renamed to Dean Wyant knows little about programming. Pin
    Dean Wyant30-Apr-04 11:11
    memberDean Wyant30-Apr-04 11:11 
    GeneralA good Parser Pin
    stocklab18-Jan-01 18:57
    memberstocklab18-Jan-01 18:57 
    GeneralRe: A good Parser Pin
    Ping He10-May-01 0:36
    memberPing He10-May-01 0:36 
    GeneralRe: A good Parser Pin
    MathePeter3-Jul-07 4:22
    memberMathePeter3-Jul-07 4:22 
    GeneralDoes not understand decimals Pin
    Anonymous3-Nov-00 5:55
    sussAnonymous3-Nov-00 5:55 
    QuestionBugs etc. - How does it deserve such high ratings? Pin
    Dean Wyant23-May-00 14:59
    sussDean Wyant23-May-00 14:59 
    QuestionEnglish translation of comments? Pin
    Peter Helmers10-Apr-00 5:03
    sussPeter Helmers10-Apr-00 5:03 
    GeneralFunctionParser Pin
    Armin Zürcher12-Mar-00 2:57
    sussArmin Zürcher12-Mar-00 2:57 

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