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hi
i have a problem with programing in c#
i need to convert a string data such as ( z = x*y+2 ) to a mathematical formule
please help me to solve it 
my mail : hosseinyaghmaee@yahoo.com
thanks for your help 
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This is not an easy thing to do... ii was trying something similar recently...parsing a formula and tunring it into a graph (eg y=2x or y=x^2).
You have not said what you wan to do with the "formula" after it is parsed...i asuume something like fill in 2 of the 3 variables and have it calculate the third. In which case you need to solve the equation to some extent as well as parse it.
Take a look at a Design Pattern called Interpreter[^] as this is often used for writing programming or scripting languages. You want a simple scripting language with just mathematical operators.
Alternatively, somebody out there would have wriiten this already, you could search google and find something very easily.
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Or use Polish notation for simpler parser. In this kind of notation, you don't need brackets:
( 3 * ( 3 + 7 ) % 2 ) / 17
standard notation
/ % * + 3 7 3 2 17
Polish notation, I think
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Thats a good idea! Well remembered. Many of the simple parsers out there on the web use this notation as its much simpler to build the parse tree.
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Converting from infix to reverse polish notation's a trivial task, that only involves feeding tokens to stacks.
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How can this be done? I'm talking about the small icon that appears at the top-left of your windows application. If you have more .NET applications running it's annoyng 'cause they look the same in the taskbar. Thanks
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I am a bad person. I thought your response both articulate and appropriate to the question, then voted you a 1 rather than 5 
Rhys
A bus station is where a bus stops. A train station is where a train stops. On my desk I have a workstation...
Vampireware /n/, a project, capable of sucking the lifeblood out of anyone unfortunate enough to be assigned to it, which never actually sees the light of day, but nonetheless refuses to die.
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Does anyone know if it's possible to compile a C# project in such a way that i can run the exe on a pc that does not have the .Net framework installed...?
compile directly to machine language instead if IL or something along that line 
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Its just not possible or feasable.
MS has a research compiler (codename 'Bartok') that can do this (static compilation to x86), but for security and versioning reasons, I doubt the public will ever get to see it. 
xacc-ide 0.0.99-preview7 now with C#, C, C++, IL, XML, Nemerle, IronPython, Perl, Caml, SML, Ruby, Flex, Yacc, Java, Javascript, Lua, Prolog and Boo highlighting support!
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There i$ commercial $software to do thi$. It'$ not cheap though.
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You could buy thinstall.
Wout
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I want to extract the key information from a Digital Certificate
X509Certificate class can be used to get the public key but i couldnt find ny method to get the private key. is it possible ??
Regards,
Rizwan Ahmed Malik
R A M
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I have a form with a Button1 that when clicked, it creates several controls on an area (not a panel control).
button2 creates different controls on the same area.
is there a way to clear all controls on a defined are?
let say, I want to reset the area 200x200 before either button is pressed.
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I'd say the easiest way would be to create a panel and put the controls on that panel. Then you can get rid of them with Panel.Controls.Clear();
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In c#， I run SQL statement for Oracle database.
When I create trigger, there is a bug.
I could run the same statement in SQL plus of Oracle and create a trigger.
However, SQL in C# created nothing.
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Hi,
what if I have a Page subclass A.cs with a protected attribute "foo" and I use it in A.aspx.cs ?
what if many users request page A ? what value of "foo" will they see ?
Class A:
<br />
public class A : System.Web.UI.Page {<br />
<br />
protected string foo;<br />
<br />
private void Page_Load(object sender, System.EventArgs e) {<br />
foo = "hi there " + Request["AUTH_USER"];<br />
}<br />
<br />
...<br />
Page A:
<br />
<%@ Page language="c#" Codebehind="A.aspx.cs" AutoEventWireup="false" Inherits="some.A" %><br />
<html><br />
<body><br />
<%=foo%><br />
<br />
...<br />
Thanks in advance for your reply
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An instance for the Page class is created for every request.
xacc-ide 0.0.99-preview7 now with C#, C, C++, IL, XML, Nemerle, IronPython, Perl, Caml, SML, Ruby, Flex, Yacc, Java, Javascript, Lua, Prolog and Boo highlighting support!
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So it does not do some sort of object pooling ?
for every request it creates an object from that class, serve the request, destroy the object ? 
well... ok, thanks!
----------------------
!happy coding!
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zu78 wrote: for every request it creates an object from that class, serve the request, destroy the object ?
AFAIK yes, silly isnt it?
static instances are persisted on application level, but be aware ASP.NET tends to go into 'sleep' mode and the values get reset.
Other option is to use the Session object. You can just save object instances there that will be persisted for the current session of the user, which is porbably what you are looking for 
Eg:
string id = Session["login"] as string;
...
xacc-ide 0.0.99-preview7 now with C#, C, C++, IL, XML, Nemerle, IronPython, Perl, Caml, SML, Ruby, Flex, Yacc, Java, Javascript, Lua, Prolog and Boo highlighting support!
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leppie wrote: You can just save object instances there that will be persisted for the current session of the user, which is porbably what you are looking for
Err... no. What I want is a method of passing objects between a class and it's subclass in a concurrent-access-safe-manner and only in the scope of a request/response (I need something like java's Request.setAttribute).
ViewState is great, but IMHO only for intranet applications.
But, if your answer is correct... I've found it.
Thanks!
----------------------
!happy coding!
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leppie wrote: static instances
Oxymoron alert
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J4amieC wrote: Oxymoron alert
Ok, wise ass, what would you call it? Maybe not techinically correct, but everyone (bar you) seems to understand it as "an instance of a class that is a static member in some class". 
xacc-ide 0.0.99-preview7 now with C#, C, C++, IL, XML, Nemerle, IronPython, Perl, Caml, SML, Ruby, Flex, Yacc, Java, Javascript, Lua, Prolog and Boo highlighting support!
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lol calm down... it was a bit of sarcasm.
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Hello,
I have a bizarre problem that i've boggled my mind about for awhile. I just can't figure this one out. Ok, I have an ITEMIDLIST structure in C# and I've defined the COM IShellFolder interface. Here's the problem:
I want to retreive the icon for the desktop using the system image list and the SHGetFileInfo folder. The only way to do this is to pass the SHGFI_PLID flag with the ITEMIDLIST structure converted to an LPCSTR (this is how you do it in C++). In C# i have to pass a string to the SHGetFileInfo function and I want to convert my ITEMIDLIST structure to a string with each character being the bytes of the structure.
Is there any way to do this? If i pass the string "C:/Documents and Settings/Username/Desktop", I will get the folder icon which is correct for this path. I want that little blue icon. Any ideas. If I need to be more specific, just ask and I'll try to rephrase the question.
RockmanHero2003
My computer finally got faster...I threw it out the window and it went very fast.
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