A powerful math function parser(zz)

hamo — Wed, 29 Nov 2006 16:12:30 +0000

by Andreas Jdger

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* fkt =
CFunction::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.

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Tags: Cpp, How-to, math, parser

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A powerful math function parser(zz)