Re: Using Methods within a Switch Case - C# Discussion Boards

DevonDaDude11-Dec-09 22:47

11-Dec-09 22:47

Hello, everyone! I'm in need of assistance. I have to write a program calculating a user's input in a switch case.. I'm having problem.. Within my switch case, I reference a method to execute if the case statement is true.

A Little about my program:

The user will be given a menu. User will then select the option they desire and the amount they would like... User can keep entering the same option over and over(which I initialize the counter).

Here's a snippet of my code.

This is a Method of the Switch:

//Switch Statement Intialize
static void SwitchIntialize(ref int userResponse)
{
    switch (userResponse)
    {
        case 1:
                GetY(out yQ, out yTotal);
            break;

        case 2:
            {
                GetZ(out zQ, out zTotal);

            }
            break;

        default:
            {
                Console.WriteLine("Sorry, You've entered an Invalid Number");
                Console.WriteLine("Please try Again!!");
            }
            break;


    }


}

Now, This is my Method

//Calculates
  static void GetY(out double yQ, out double yTotal)
  {
      const double yPrice = 60.5;
      Console.WriteLine("How many pounds would you like of  Y? ");
      yQ = Convert.ToDouble(Console.ReadLine());
      yQ += yQ;
      yTotal = yQ * yPrice;
  }//EOF GetY

  //Calculates
  static void GetZ(out double zQ, out double zTotal)
  {

      const double zPrice = 20.39;
      Console.WriteLine("How many pounds would you like of Z? ");
      zQ = Convert.ToDouble(Console.ReadLine());
      zQ += zQ;
      zTotal = zQ * zPrice;


  }//EOF z

For my final output, I will have to display how many lbs of X,Y, and Z the user purchase and the price of it..

I've also, declare it in my main as,

SwitchIntialize(ref int userChoice)

The Errors, that I've encountered are:

The Name yQ does not exist in the current context.
The name yTotal does not exist in the current context.
The best overloaded method match 'Program.GetY(out double, out double); has some invalid arguments
Argument '1': cannot convert from 'out yQ' to 'out double'
Argument '2': cannot convert from 'out yTotal' to 'out double'

The Name zQ does not exist in the current context.
The name zTotal does not exist in the current context.
The best overloaded method match 'Program.GetZ(out double, out double); has some invalid arguments
Argument '1': cannot convert from 'out zQ' to 'out double'
Argument '2': cannot convert from 'out zTotal' to 'out double'

Re: Using Methods within a Switch Case

Abhinav S11-Dec-09 22:56

Abhinav S

11-Dec-09 22:56

DevonDaDude wrote:
GetY(out yQ, out yTotal);

If you have you declared your variable types yQ and yTotal somewhere outside switchinitialize then declare them as static.

static double yQ;<br />
static double yTotal;

The same goes for all the other variables.

There's nothing left in my right brain and nothing right in my left brain.

Re: Using Methods within a Switch Case

OriginalGriff11-Dec-09 23:03

OriginalGriff

11-Dec-09 23:03

Why would he want to declare them as static? There would appear to be no need for a single copy of them regardless of the number of instances.

All those who believe in psycho kinesis, raise my hand.

Re: Using Methods within a Switch Case

Abhinav S11-Dec-09 23:09

Abhinav S

11-Dec-09 23:09

Simple.

I did not see any variables in his method. So he's missed them. And if he wants to declare them in the class (as class variables) he would have to declare them as static (otherwise the project would not even build). Its entirely up to him.

There's nothing left in my right brain and nothing right in my left brain.

Re: Using Methods within a Switch Case

Saksida Bojan12-Dec-09 1:49

Saksida Bojan

12-Dec-09 1:49

Abhinav S wrote:
And if he wants to declare them in the class (as class variables) he would have to declare them as static (otherwise the project would not even build)

Not true. You can declare as class variable without static method.
example:

public class myClass
{
   public myClass()
   {
      str = "This has a string";
   }

   public void WhatIsInString()
   {
      MessageBox.Show(str);
   }
   public String str;
}

static is useful when you want variable to be accessible anywhere within project

Re: Using Methods within a Switch Case

Richard MacCutchan12-Dec-09 3:08

Richard MacCutchan

12-Dec-09 3:08

Saksida Bojan wrote:
public String str;

That's not a class variable, it's an instance variable. Class variables are static, i.e. there is only one copy regardless of how many instances of the class exist. This is different from a static variable defined at the module level which does not belong to a class.

Re: Using Methods within a Switch Case

DevonDaDude15-Dec-09 18:20

DevonDaDude

15-Dec-09 18:20

Thanks, everyone.. Abhinav, thank you as well, I use private static double yQ; and I got it working. Thanks Smile | :)

Re: Using Methods within a Switch Case

OriginalGriff11-Dec-09 23:01

OriginalGriff

11-Dec-09 23:01

From the error messages, I think you need at add a few statements to your method, just amove the switch:

double yQ;
double yTotal;
double zQ;
double zTotal;

This will declare the missing variables, and should get rid of the error messages.

From a stylistic point of view, have you noticed how similar your two routines getY and getZ are? Perhaps you could combine them into one, so it would be easier to maintain?

All those who believe in psycho kinesis, raise my hand.

Re: Using Methods within a Switch Case

PIEBALDconsult12-Dec-09 3:59

PIEBALDconsult

12-Dec-09 3:59

0) You probably want to use ref rather than out unless you're somehow calculating the total after the switch.

1) There's no need to assign yQ/zQ twice.

zQ += Convert.ToDouble(Console.ReadLine());

And why not use double.TryParse ? And handle bad input?

2) Pay better attention to the teacher and your textbook.

Re: Using Methods within a Switch Case

DevonDaDude12-Dec-09 15:45

DevonDaDude

12-Dec-09 15:45

Thanks everyone, for your input..I do appreciate it.. I'll try all of the above..

Someone said, I should
* Declare all the variables use - I did declare it, I just gave small snippet of the code.
* No Need to assign yQ/zQ - I'm applying what i've learned, I was unaware I could do something like that.
* Double.TryParse - I'm unfamiliar with that, I only know what my book and teacher, taught us.
* I do pay attention to the teacher and my textbook.
* I cannot change it to a if..else statement.. The requirements for this program is to use switch case.

Again, I do appreciate all of your inputs. Thank You, Very Much! Smile | :)

Use of << and >> [modified]

Joe Rozario11-Dec-09 19:16

Joe Rozario

11-Dec-09 19:16

Dear friends,

Can someone please Explain me about << and >> operator

and diffrence between | and || operator

and where it can be Used. and some example please

by

joe

modified on Saturday, December 12, 2009 1:35 AM

Re: Use of << and >>

Abhinav S11-Dec-09 19:56

Abhinav S

11-Dec-09 19:56

Try here [^].

There's nothing left in my right brain and nothing right in my left brain.

Re: Use of << and >> [modified]

DaveyM6911-Dec-09 21:27

DaveyM69

11-Dec-09 21:27

<< and >> do a bitwise shift in the indicated direction the specified number of places. Think of them like n x 10 and n / 10 in decimal (base 10), but in binary (base 2) so they are effectively n * 2 and n / 2 if shifting by one.

| does a bitwise OR where each binary digit is ORed with it's counterpart. This is the OR truth table for each bit in two values being ORed, the first column is the first value, the second column is the second value and the final column is the result:

--------
|0|0||0|
|0|1||1|
|1|0||1|
|1|1||1|
--------

A logical OR || is the same except it can only operate on a boolean value and returns a boolean, so replace the 0s in the table with false and the 1s with true.

Unless you're doing binary operations then you won't use them every day. One place I had to use them recently is in getting/creating the constituent bytes of a MIDI packet. All 'short' MIDI messages are between 1 and 3 bytes long. An Int32 is 4 bytes so Microsoft chose to place all packets in one Int32. If I use a NoteOn as an example:

1001cccc : byte0 = status (c = channel)
0nnnnnnn : byte1 = note number
0vvvvvvv : byte2 = velocity

As an Int32: xxxxxxxx0vvvvvvv0nnnnnnn1001cccc

So to build this Int32 from 3 bytes status, note, velocity) I need to start with status, then left shift note by 8 bits and velcity by 16 bits then OR them all.

Int32 intStatus = status;
Int32 intNote = (note << 8);
Int32 intVelocity = (velocity << 16);
Int32 packet = intStatus | intNote | intVelocity;

To get the bytes out, a 'mask' is needed and a logical AND combined with a right shift

Int32 statusMask = 0x000000FF;
Int32 noteMask = 0x00007F00;
Int32 velocityMask = 0x007F0000;

byte status = (byte)(packet & statusMask);
byte note = (byte)((packet & noteMask) >> 8);
byte velocity = (byte)((packet & velocityMask) >> 16;

Dave

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

modified on Saturday, December 12, 2009 1:38 PM

Re: Use of << and >>

Joe Rozario11-Dec-09 21:46

Joe Rozario

11-Dec-09 21:46

Thank you friend...thanks for your replay.

i could not understan your code fully but i got somthing about the operator

thank U

Re: Use of << and >>

DaveyM6911-Dec-09 22:37

DaveyM69

11-Dec-09 22:37

You're welcome Smile | :)

In case you want to improve your English, it's 'reply' not 'replay' - a common mistake Thumbs Up | :thumbsup:

Dave

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

Re: Use of << and >>

Joe Rozario16-Dec-09 17:59

Joe Rozario

16-Dec-09 17:59

Thank You... Wink | ;)

Re: Use of << and >>

harold aptroot11-Dec-09 21:45

harold aptroot

11-Dec-09 21:45

There are many examples on Bit Twiddling Hacks[^]

How to show multiple crystal reports in single Report Viewer. [modified]

sher_azam11-Dec-09 18:35

sher_azam

11-Dec-09 18:35

Hello Friends,
i am working in a desktop application in VS 2008 using C#. And i am creating some crystal reports against search records. Say i have generate my reports against a Selected Client. Generate crystal report against single client is simple and straight forward.
Now i want to select multiple clients and generate there reports and want to display all of them in single viewer. so i can achieve this?
Second reports will show after the end of first report and will be on next page but in same viewer.
Please help me to achieve this functionality. If possible let me know some sample code for this.
Thanks
Sher Azam

modified on Saturday, December 12, 2009 1:31 AM

Re: How to show multiple crystal reports in single Report Viewer.

Abhinav S11-Dec-09 23:02

Abhinav S

11-Dec-09 23:02

Could you design all of your reports as sub reports?

There's nothing left in my right brain and nothing right in my left brain.

Re: How to show multiple crystal reports in single Report Viewer.

sher_azam11-Dec-09 23:13

sher_azam

11-Dec-09 23:13

actually the number of sub reports can be any that's why i am not preferring it. is there any other solution that i can add multiple reports of same type in single viewer.

Custom User Control for Multipoint SDK!

Kushal Gautam11-Dec-09 17:53

Kushal Gautam

11-Dec-09 17:53

Hi:

As everyone might be aware of Microsoft Multipoint SDK, I have been trying to do a project based on this SDK.

This SDK provides us the capability to use several mice on a single computer(obviously several cursors). Everything is fine, but it has only two controls, namely; Multipoint Button and Multipoint TextBox. Now, what if I need to have my own user control?? Please help me out. I am jus stuck.

Thanks.

Re: Custom User Control for Multipoint SDK!

krunal255-Feb-10 1:53

krunal25

5-Feb-10 1:53

HI,
I have createad a custom control for MultipointSDK for making my game with it
You could visit the post on this link
social.msdn.microsoft.com/Forums/en/mptgen/thread/470ba298-0617-4da4-9ba3-bfa0e359e994
Ok you would get the idea Smile | :)

Good bye

threading, invoke

benjamin yap11-Dec-09 16:52

benjamin yap

11-Dec-09 16:52

Hi,

I got this chart object on my UI thread called 'm_ChartControl'

I got a method called AddAnnotations that will be run on a new thread in my Form_Load method.

Inside my AddAnnotation method there is a line of code that do this.

Annotation a = m_ChartControl.Charts[0].AnnotationList.CreateAnnotation();

But m_ChartControl.Charts[0].AnnotationList.CreateAnnotation(); is in the UI thread.

How do i create a delegate to put it here?

I have tried this.

private delegate Annotation AddAnnotation();
AddAnnotation addNewAnnotation;
private Annotation CreateAnnotation()
{
    return m_ChartControl.Charts[0].AnnotationList.CreateAnnotation();
}
void cAnnotation()
{
    this.Invoke(addNewAnnotation);
}

I changed this to

Annotation a = cAnnotation();

and i get this error

Error 18 Cannot implicitly convert type 'void' to 'Manco.Chart.CF.Layout.Annotation'

Re: threading, invoke

Saksida Bojan12-Dec-09 1:58

Saksida Bojan

12-Dec-09 1:58

Threading in .NET and WinForms[^]

void cAnnotation()
{
AddAnnotation del = new AddAnnotation();
this.Invoke(del);
}

public Annotation()
{
//This function will be referenced and executed on destination form/control
}

SerialPort UART input buffer omits zeroes

Karthik S Prakash11-Dec-09 15:18

Karthik S Prakash

11-Dec-09 15:18

Hi,

I need to tranfer hex values through UART. But the problem is the default ASCII encoding of the SerialPort omits zeroes and such values (mostly below 0x14). What do I change this setting to in order to receive all values from 0-255 through the port? Please Help.

For ex: 0x55, 0x55, 0x00, 0x00, 0x55, 0x55 comes through to the PC C# app as UUUU

Regards,

Karthik

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