Extracting Variables from Strings and Event for a Tabchange in a TabControl

I have a program that is meant to take a user defined string (ex. x2 + 2x + 1) and divide it, and then store those values (the coefficents of x); there is a practically indefinite number of numbers in the coefficient.

I've looked at the String.Split Method, but I don't understand it very well nor do I believe it's very practical when you have to keep splitting each variable to get the coefficient. Is there an easier way to the the opposite of concatenation

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Unrelated to my previous question, I also need to have some things(generate a MsgBox and set variable values) when the tab of a tab control is changed. I've read about what I believe is the event, but once again, I am not totally sure how to use it because I am not familiar with raising events. How would I go about doing this

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Extracting Variables from Strings and Event for a Tabchange in a TabControl

milTash

No, it's not solved...

I still don't know an efficient way to extract the variables from the textbox's text.
Giusy Provvidenti

you don't have to raise the event the control will.

You do, however have to declare the event handler.

in edit mode...

In the upper left hand window, select the tab control. Then in the right hand window, select the selectionchanged event. This will insert the event handler in your source code for you to code.
alok ranjan
Specifically, what I want to have is code that takes a string entered into a textbox such as

9x2 + 8x + 7

In my program, I need to take the number from this string and store it as a variable for computation. The pieces "x2 + " and "x + " always remain constant. Is there code that will do this for me and if so what is it

Before I was speaking about a command that I had read a little bit about: String.Split. However, from what I do understand about it, it would take numerous lines of code to do the one seemingly simple task that I need it do.

http://users.cjb.net/jontec7/quadratic%20equation.exe
Tamoxifeno
hi,

Is your problem solved

Thank you,
Bhanu.
Malla
I researched regex, and it looks like exactly what I need. However, I did not see any Visual Basic examples in the explanation. I had to look at the C++ end to understand what they were talking about (I don't know C++!).

Regex.Replace had an example and it looks like it just about solves my problem, except for the fact that it would return (as in our first example) 987, which is not anything that I could work with.

Does anyone have any ideas about this Is there another Regex.* that I can use
Varsha
Here's what I think that I am going to do.

We start out with the input: 9x2 + 8x + 7.
I use Regex.Replace to get rid of the spaces " " and the Xs "x".
It returns: 9+8+7

From here I use the String.Split to return an array of 9, 8, 7.

Finally
array(0) is stored as variable (integer) a
array(1) is stored as variable (integer) b
array(2) is stored as variable (integer) c

And with these variables I can do the computation that I need.
I'll reply back with my result and the code that I use.
Jvalente
maybe you can try using regular expression
just check out System.Text.RegularExpressions

regular expression(or regex) gives much more flexibilities in text manipulations
but it has a somewhat steep learning curve for beginners
Francy
You need a beast called Bison to parse expressions like this. Google for Yacc and Lex.
Margriet

Hi jon,

your first question is not so clear.Somewhere i can't understand english like this "but I don't understand it very well nor do I believe it's very practical ".

can you please explain in simple english what you want exactly

and for second question. I hope you already got Ans.

msgbox("Tab page changed") insteed of you can use

Messagebox.Show("Tab page changed")
Extracting Variables from Strings and Event for a Tabchange in a TabControl

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