how to use switch case for a range of number

Question

_{Saturday, August 1, 2009 3:37 PM}

As above...  could this statement work ?  case (0 - 500)

public void Switch(int num)
{
  switch (num)
  {
    case (0-500):
      // belong to 0-500;
     break;
    case (501-1000):
       // belong to 501-1000;
      break;
  }
}

All replies (12)

_{Saturday, August 1, 2009 3:50 PM ✅Answered}

You can't really do that with a switch.

You can do:

if (num >= 0 && num <= 500) { ........}
else if (num >= 501 && num <= 1000) {.............}John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

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_{Saturday, August 1, 2009 4:00 PM ✅Answered}

You can do it with small ranges of numbers like so:

switch (myInt)
{
    case 0:
    case 1:
    case 2:
        // do something
        break;
    etc...
}

But I definately wouldn't recommend that for 500 of em.

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_{Saturday, August 1, 2009 4:01 PM ✅Answered}

The answer is NO!

See the same question and answer here:
http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/c46bee82-ac9a-4f15-bcc0-9e5baa557916/

VB can do it but not C#. People suggested using if/else.

Oh, by the way, (0 - 500) is an expression and
(0 - 500) = -500 

---

John Chen -- See my team blog: http://blogs.msdn.com/vsdata

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_{Saturday, August 1, 2009 4:59 PM ✅Answered}

Hi,
After I see all this answers there is no comment they are right you can't, so the best solution With such large ranges it is easier to use if - else if statements.

 Thanks

 

We are volunteers, if the reply help you mark it as your answer. thanks!!
My Blog

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_{Saturday, August 1, 2009 5:24 PM ✅Answered | 3 votes}

As long as it is a range with a constant interval, you can map the range to an integer:

  int range = (num-1) / 500;
  switch (range) {
    case 0: break; // 1-500
    case 1: break; // 501-1000
    // etc...
  }

if/else for non-constant intervals.

Hans Passant.

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_{Saturday, August 1, 2009 3:48 PM}

Have you tried it?  Posting takes longer than testing in the IDE.

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_{Saturday, August 1, 2009 4:00 PM}

JohnWein, that doesn't work in C# unfortunately. The switch only deals with constants
John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

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_{Saturday, August 1, 2009 4:06 PM}

JohnWein, that doesn't work in C# unfortunately. The switch only deals with constants

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

What doesn't work in C#?  You can certainly write code that doesn't work in the IDE.  Try it.

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_{Saturday, August 1, 2009 4:13 PM}

Read the documentation here on switch

switch (expression)

{

   case constant-expression
:

      statement

      jump-statement

   [default:

      statement

      jump-statement]

}

John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

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_{Saturday, August 1, 2009 4:36 PM}

Read the documentation here on switch

switch (expression)


{


   case constant-expression

:


      statement


      jump-statement


   [default:


      statement


      jump-statement]


}

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

If this post is for my benefit, read my original post in this thread.  The OP should have been able to answer his question without posting it to a forum.  If you need assistance start a new thread.

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_{Saturday, August 1, 2009 5:08 PM}

It wasn't directed at you JohnWein, it was meant for all, generally speaking.
John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

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_{Tuesday, November 11, 2014 12:25 PM}

As long as it is a range with a constant interval, you can map the range to an integer:

  int range = (num-1) / 500;
  switch (range) {
    case 0: break; // 1-500
    case 1: break; // 501-1000
    // etc...
  }

if/else for non-constant intervals.

Hans Passant.

Good logic.