Re: Calculate and Display Prime Numbers - C# Discussion Boards

coolestCoder21-Mar-07 18:35

coolestCoder

21-Mar-07 18:35

Darkness84 wrote:
I am working on an application that maintains an open connection to an sql database

First of all, I would like to know the conditions under which you need an open connection to the database (always) ?
I think you can open the connection just at the time of your query execution. what is the problem in this kind of scenario ?
Persisting database connections will load your database server. I dont think that this is desirable.

"A good programmer is someone who looks both ways before crossing a one-way street." -- Doug Linder

coolestCoder

Darkness8421-Mar-07 18:40

Darkness84

21-Mar-07 18:40

I am using SqlDependency so that my application will respond immediately to changes in the database and thus i need the connection to be open.

coolestCoder21-Mar-07 19:15

coolestCoder

21-Mar-07 19:15

Hi,
I dont know much about the SqlDependency, here[^] is an article on CP, which specifies (at the last) that the connection need not be open to recieve change event. Will this solve your problem ?

"A good programmer is someone who looks both ways before crossing a one-way street." -- Doug Linder

coolestCoder

Darkness8421-Mar-07 19:20

Darkness84

21-Mar-07 19:20

Not sure, but I'll have a read. Thanks.

chitra4sat21-Mar-07 18:05

chitra4sat

21-Mar-07 18:05

Hi All,

I am an Student and learning C#. my work is to write a class for calculating the number which is prime number and w ehave to call that method in a main program to display the output.

And i have to get the number from the user end using the Console.ReadLine().

No array declaration only using the for loop or the if else condition loop.

please help me in coding for calculating the Prime Number.

Awaiting your response ASAP.

Regards,

Chitra

sherifffruitfly21-Mar-07 18:11

sherifffruitfly

21-Mar-07 18:11

You want us to do your homework for you? Seriously?

Leslie Sanford21-Mar-07 18:33

21-Mar-07 18:33

chitra4sat wrote:
And i have to get the number from the user end using the Console.ReadLine().

Does this mean that your program is suppose to determine if a number entered by a user is prime?

Design your algorithm for determining whether a number is prime. Definition: An integer p is called a prime number if the only positive integers that divide p are 1 and p itself. Integers that are not prime are called composite. [^]

Aside from the number 2, we can eliminate all even numbers because all even numbers are evenly divisible by 2. For more details on optimizing a prime number algorithm, be sure to google. You'll find lots of stuff. This should get you started. If you have any questions, feel free to ask.

chitra4sat21-Mar-07 19:27

chitra4sat

21-Mar-07 19:27

Thanks Guyz,

I have tried it as this but the problem is i have to put all the methods in a another class progam such as PrimeNumClass.cs and i have to call that in the main program to display the output.

here is my code:

<br />
namespace PrimeNumber<br />
{<br />
    class Program<br />
    {<br />
        static void Main(string[] args)<br />
        {<br />
            // declare variables<br />
            int n = 2;<br />
            int totalPrimeNumbers = 0;<br />
            int x;<br />
            double sumOfPrimes = 0;<br />
<br />
            // while loop when n <= 100<br />
            while (n <= 100)<br />
            {<br />
                bool isPrime = true;<br />
<br />
                // test if n is prime<br />
                for (x = 2; x < n; x++)<br />
                {<br />
                    if ((n % x) == 0)<br />
                    {<br />
                        isPrime = false;<br />
                        break;<br />
                    }<br />
                }<br />
<br />
                if (isPrime == true)<br />
                {<br />
                    Console.WriteLine(n + " is a prime Number.");<br />
<br />
                    sumOfPrimes = sumOfPrimes + n;<br />
                    totalPrimeNumbers++;<br />
                }<br />
                n++;<br />
            }<br />
           <br />
<br />
        }<br />
    }<br />
}<br />

Here everything is in Main Program itself. But i want it all in a seperate class Nmaed PrimeNumClass.cs and i have to call that class in the main Class to display the output.

please help me. itz very urgnet.

regards,

Chitra

Leslie Sanford21-Mar-07 19:37

21-Mar-07 19:37

chitra4sat wrote:
Here everything is in Main Program itself. But i want it all in a seperate class Nmaed PrimeNumClass.cs and i have to call that class in the main Class to display the output.

Creating a new class is easy. Just right click on your project and click on Add then Class from the pop menu. Fill in the text box with the name of your of your class, in this case, PrimeNumClass.

The IDE will create a source file for you that looks like this:

using System;
using System.Collections.Generic;
using System.Text;
 
namespace PrimeNumber
{
    class PrimeNumClass
    {
    }
}

Now, once you get to this point, you need to add a method to the class that contains your prime number algorithm. In this case, it would probably be best to make the method static. Also, make sure that it has public access so that it can be called from your Main function.

I'm going to leave it here and let you take over. If you have any problems, feel free to ask.

chitra4sat21-Mar-07 19:48

chitra4sat

21-Mar-07 19:48

Hi Thanks,

I have created it as you said the PrimeNumClass as you have mentioned .

but what are all the things have to be inside that class and let me know it by code.

becoz i have the output in the main program and all the funcctions are carried out there. but i have been asked that in the main program there should not be anything but we have to create the object and w ehave to call that method to display the output of the prime number.

so please help me what to do ?

Leslie Sanford21-Mar-07 20:00

C# Automation Addin for Excel using ,NET - Build Error - Cannot Register Assembly (MSB3217)

21-Mar-07 20:00

chitra4sat wrote:
but what are all the things have to be inside that class and let me know it by code.

becoz i have the output in the main program and all the funcctions are carried out there. but i have been asked that in the main program there should not be anything but we have to create the object and w ehave to call that method to display the output of the prime number.

You need to add a method to your PrimeNumClass. For example, in your Program class, you have a method named Main. When you run your console application, the application invokes your Main method.

So add a method to your PrimeNumClass. You need to give your method a name, return type, and specify its access. In addition you need to decide if your method takes any arguments. For example, below is a class with no methods:

namespace ClassDemo
{
    public class MyClass
    {
    }
}

Now, let's add a method to it that doesn't return anything and takes no arguments:

namespace ClassDemo
{
    public class MyClass
    {
        public void SayHello()
        {
            Console.WriteLine("Hello!");
        }
    }
}

The class now has a method called SayHello. If I want to use this class, I can create an instance of it and invoke the SayHello method:

MyClass mc = new MyClass();
 
mc.SayHello();

Based on what I've shown you here, add a method to your PrimeNumClass. Then put the code you have in your Main method into this method.

ralph_y21-Mar-07 17:58

ralph_y

21-Mar-07 17:58

I am trying create an Automation Add-in for Excel using .NET as per http://blogs.msdn.com/eric_carter/archive/2004/12/01/273127.aspx[^], and http://www.codeproject.com/dotnet/excelnetauto.asp[^] using SharpDevelop V2.00. Having chosen to 'Register for Com Interop" in the project properties, a build produces the error "Cannot Register Assembly. Exception has been thrown by the target of an invocation. (MSB3217) Microsoft.Common.Targets."

As a complete newbie to C# and knowing nothing about .NET and COM, searching through forums and google on the error message, I still have no clues as to how to get rid of the error.

Can anyone point me in the right direction?

How to remove the rectangle from Propertygrid ?

TaiZhong21-Mar-07 17:03

TaiZhong

21-Mar-07 17:03

I'd like to change the way the value displayed in the grid.
So I create a class which derived from UITypeEditor and I have overriden the GetPaintValueSupported and PaintValue methods. Unfortunately there is a small rectangle display in the grid. Is there a way to remove this rectangle? So that I can draw whatever I want.

Thanks in advance....

Re: How to remove the rectangle from Propertygrid ?

visualhint16-Apr-07 3:33

visualhint

16-Apr-07 3:33

Unfortunately this is impossible to get rid of this rectangle. It is painted internally AFTER your have painted inside the rectangle.

Best regards,

Nicolas Cadilhac
Smart PropertyGrid.Net @ VisualHint
Microsoft PropertyGrid Resource List
Free PropertyGrid for MFC

block website function by enterring in texbox in a form.need help here

krajah1021-Mar-07 15:26

krajah10

21-Mar-07 15:26

How is the function for block website that have been enter in text box and click add button it will appear in listbox. All this is in one form only.And another button for remove the web site have been add in listbox. The web site have been block will block by browser and this web site cant be acess. Please help me.Thanks A lot.
Below are the coding for the web site bloking form:
//List box
private void listBox2_SelectedIndexChanged(object sender, EventArgs e)
{

}
//TextBox
private void textBox3_TextChanged(object sender, EventArgs e)
{

}

//Add button
private void Add_Click(object sender, EventArgs e)
{

}

//Remove
private void Remove_Click(object sender, EventArgs e)
{

}
Tq...

thread question

dino209421-Mar-07 14:51

dino2094

21-Mar-07 14:51

I writing an windows app in C# that receives data via serial port.
I have a thread dedicated to reading from the serial port and when
it has a full packet, it makes a call to the main form.

CallBackUpdate callBack = new CallBackUpdate(updateState);<br />
Invoke(callBack, new object[] { newPacket });<br />

So it passes the newPacket to a method called updateState.

Lets say this happens: (Although I don't think it will)

1.Receive one packet and is sent to main form for processing.
2.Receive another packet and send it to main form before packet from 1 is done processing.

Question/Concern

Will the main form process the first packet completely before it processes the second?

or

Do I have to add some blocking to the serial thread so that it doesn't send a packet for
processing when another is being processed.

Re: thread question

Leslie Sanford21-Mar-07 17:02

Program structure need experienced programmers perspective please

21-Mar-07 17:02

dino2094 wrote:
Invoke(callBack, new object[] { newPacket });

Careful here. This will block until the Form invokes the delegate and it completes. Your serial port thread won't be able to do anything else. Perhaps try BeginInvoke instead.

dino2094 wrote:
Will the main form process the first packet completely before it processes the second?

Yes.

dino2094 wrote:
Do I have to add some blocking to the serial thread so that it doesn't send a packet for
processing when another is being processed.

Well, you get that for free by using Invoke rather than BeginInvoke. But I'm betting you'd probably want to use BeginInvoke instead.

Mischievious21-Mar-07 14:36

Mischievious

21-Mar-07 14:36

Program type: preferably windows service

Program Description

Part 1: polls sql table for recs with certain criteria (needs to check every minute or so)

Part 2: If part 1 finds recs that match, then part 2 needs to retrieve those records and do some work to them. (convert the records data into a xml document)

Part 3: The newly created xml document needs posted to a clients website (which gives a response of an error code or confirmation #)

Part 4: The original sql record needs updated with the confirmation and a flag signifying the task is done.

I am having problems figuring out how this should be done.. for instance if part 1 is checking every minute by using a timer if parts 2 - 4 haven't completed after part 1 has notified them the first time it might try to notify about the same records again

How would you keep everything organized

Re: Program structure need experienced programmers perspective please

Leslie Sanford21-Mar-07 17:05