Switch question

Question

User218791533 posted

How would you write this in C#?

Select Case Asc(tChr)
Case 65 To 90, 97 To 122, 48 To 57
End Select

Thanks

Answer 1

User281315223 posted

C# doesn't support ranges for switch statements like Visual Basic does.

The easiest approach might be to use an explicit if-statement that checks to see if it falls into your specific range. Additionally, the Asc() function returns an integer that corresponds to a certain character, which you could use by just converting the character to an integer as seen below :

// Get your integer value
var x = Convert.ToInt32(tChr);

// Determine if it falls into your range
if(x >= 65 && x <= 90)
{
     // Case 1: 65 - 90
}
else if(x >= 97 && x <= 122)
{
     // Case 2: 97 - 122
}
else if(x >= 48 && x <= 57)
{
     // Case 3: 48 - 57
}

or if you needed to trigger an event for any of these, just use :

// Get your integer value
var x = Convert.ToInt32(tChr);

// Determine if it falls into a range
if((x >= 65 && x <= 90) || (x >= 97 && x <= 122) || (x >= 48 && x <= 57))
{
     // It falls into one of these ranges
}

Finally, if you wanted a more exact conversion, it would simply require you to list out all of the ranges similar to below :

switch(Convert.ToInt32(tChr))
{
      case 48:
      // Enumerate until 56 here
      case 57:
             // Cases 48 - 57
      break;
      case 65:
      // Enumerate until 89 here
      case 90:
             // Cases 65 - 90
      break;
      case 97:
      // Enumerate until 111 here
      case 112:
             // Cases 97 - 112
      break;
}

Answer 2

User-434868552 posted

@Confused Dav...  TIMTOWTDI =. there is more than one way to do it

Dave, you're simply trying to determine whether your value is a uppercase or lowercase letter, or a digit.

Better is to allow the MSDN Framework to do that for you.

"Char.IsLetterOrDigit Method (Char)" http://msdn.microsoft.com/en-us/library/cay4xx2f%28v=vs.110%29.aspx

Here's a simpler solution based on Char.IsLetterOrDigit:

Char space = ' '; // Decimal  32
Char star  = '*'; // Decimal  42
Char slash = '/'; // Decimal  47
Char zero  = '0'; // Decimal  48
Char nine  = '9'; // Decimal  57
Char colon = ':'; // Decimal  58
Char at    = '@'; // Decimal  64
Char A     = 'A'; // Decimal  65
Char Z     = 'Z'; // Decimal  90
Char Lbrak = '['; // Decimal  91
Char btick = '`'; // Decimal  96 
Char a     = 'a'; // Decimal  97
Char z     = 'z'; // Decimal 122
Char curly = '{'; // Decimal 123

Console.WriteLine("[{0}] {1}", space, Char.IsLetterOrDigit(space));
Console.WriteLine("[{0}] {1}", star, Char.IsLetterOrDigit(star));
Console.WriteLine("[{0}] {1}", slash, Char.IsLetterOrDigit(slash));
Console.WriteLine("[{0}] {1}", zero,  Char.IsLetterOrDigit(zero));
Console.WriteLine("[{0}] {1}", nine,  Char.IsLetterOrDigit(nine));
Console.WriteLine("[{0}] {1}", colon, Char.IsLetterOrDigit(colon));
Console.WriteLine("[{0}] {1}", at,    Char.IsLetterOrDigit(at));
Console.WriteLine("[{0}] {1}", A,     Char.IsLetterOrDigit(A));
Console.WriteLine("[{0}] {1}", Z,     Char.IsLetterOrDigit(Z));
Console.WriteLine("[{0}] {1}", Lbrak, Char.IsLetterOrDigit(Lbrak));
Console.WriteLine("[{0}] {1}", btick, Char.IsLetterOrDigit(btick));
Console.WriteLine("[{0}] {1}", a,     Char.IsLetterOrDigit(a));
Console.WriteLine("[{0}] {1}", z,     Char.IsLetterOrDigit(z));
Console.WriteLine("[{0}] {1}", curly, Char.IsLetterOrDigit(curly));

output:

[ ] False
[*] False
[/] False
[0] True
[9] True
[:] False
[@] False
[A] True
[Z] True
[[] False
[`] False
[a] True
[z] True
[{] False

But there's a catch ... the .NET Framework is a Unicode world:

Char a2dot = 'ä'; // a with umlaut

Console.WriteLine("[{0}] {1}", a2dot, Char.IsLetterOrDigit(a2dot));

output:

[ä] True

if there is any possibility that your data may contain letters like ä, ç, é, ...   et cetera, then here's a fix to stay within your range:

Console.WriteLine("[{0}] {1}", a2dot, Char.IsLetterOrDigit(a2dot) && ((Int32)a2dot<123));

output:

[ä] False