Tip/Trick

# Math Parser .NET C#

, 28 Feb 2014 GPL3
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This is light, fast and simple to understand mathematical parser designed in one class, which receives as input a mathematical expression (System.String) and returns the output value (System.Double)

## Introduction

This is light, fast and simple to understand mathematical parser designed in one class, which receives as input a mathematical expression (System.String) and returns the output value (System.Double). For example, if your input string is "√(625)+25*(3/3)" then parser returns double value — 50.

## Background

The idea was to create a string calculator for educational goals.

## How it work

For more please look at the code, I tried to explain the work of the parser in the comments and how it can be changed and extended.

Convert to RPN:

* Input operators are replaced by the corresponding token (its necessary to distinguish unary from binary).

## Using the code

Example:

public static void Main()
{
MathParser parser = new MathParser();
string s1 = "pi+5*5+5*3-5*5-5*3+1E1";
string s2 = "sin(cos(tg(sh(ch(th(100))))))";

Console.WriteLine(d1); // 13.141592...
Console.WriteLine(d2); // 0.0174524023974442
}

## Features

Ariphmetical operators :

• () — parentheses;
• + —  plus (a + b);
• - — minus (a - b);
• * — multiplycation symbol (a * b);
• / — divide symbol (a / b);
• ^ — degree symbol (a ^ b).

Functions :

Trigonometric functions:

• sin(x);
• cos(x);
• tg(x);
• ctg(x).

Hyperbolic functions:

• sh(x);
• ch(x);
• th(x).

Other functions:
• √(a), sqrt(a) — square root of a number;
• exp(x)  — exponential function (or just use e^x);
• (a)log(b) — logarithm;
• ln(x) — natural logarithm;
• abs(x) — absolute value.

Constants:

• pi — 3.14159265...;
• e — 2.71828183....

Arguments of the trigonometric functions can be expressed as radians (true) or degrees (false) by sending appropriate bool value to parse method. Example (as radians):

parser.Parse("sin(90)", true);

Work with any char decimal separator in real number (regional settings).

New operators, functions and constants can be easily added to the code.

This parser is simple (special designed in single class), convenient for the further implementation, expansion and modification.

## Points of Interest

I better understand how parsers work and learned about the reverse-polish notation.

## History

• 2012/05/09: released the source code (1_0);
• 2012/06/07: optimized parser (1_2);
• 2014/02/28: rewritten version (1_4).

## Share

Kazakstan
My full name is Yerzhan Kalzhani. I’m a pragmatic software developer who loves tasks that are interesting and challenging. My motto in software developing: "Quality, Performance and Agile".

I prefer systematic approach when solving problem, so I think that every good developer first of all should be able to manage the complexity of a software system and produce the well-structured solution for a poor defined problem.

 First Prev Next
 Excellent job jigoch 19-Dec-14 6:28
 Great Job! miro12 5-Mar-14 4:03
 Re: Great Job! kirnbas 24-Mar-14 6:35
 My vote of 4 Florian Rappl 29-Aug-12 9:50
 Re: My vote of 4 kirnbas 29-Aug-12 20:34
 Re: My vote of 4 Florian Rappl 29-Aug-12 22:27
 Re: My vote of 4 Andreas Gieriet 27-Jan-13 9:19
 Code Clifford Nelson 24-Aug-12 8:07
 Re: Code kirnbas 24-Aug-12 8:46
 Sym Warren Harding 16-Aug-12 21:32
 Re: Sym kirnbas 24-Aug-12 7:19
 Broken Image links Marcus Kramer 7-Jun-12 5:53
 Re: Broken Image links kirnbas 7-Jun-12 6:32
 I fixed it thanks for the post
 Please show and explain the code PIEBALDconsult 14-May-12 14:51
 Re: Please show and explain the code kirnbas 15-May-12 3:22
 Re: Please show and explain the code PIEBALDconsult 15-May-12 8:03
 Quite complicated expression evaluator... Andreas Gieriet 14-May-12 13:18
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