Multiple cases in switch statement

Question

Is there a way to fall through multiple case statements without stating case value  repeatedly   I know this works   switch  value       case 1     case 2     case 3           Do some stuff       break     case 4     case 5     case 6           Do some different stuff       break     default            Default stuff       break      but I d like to do something like this   switch  value       case 1 2 3           Do something       break     case 4 5 6           Do something       break     default           Do the Default       break      Is this syntax I m thinking of from a different language  or am I missing something

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One lesser known facet of switch in C  is that it relies on the operator  and since it can be overriden you could have something like this    string s   foo     switch  s      case  abc           break    case  def           break

User · Answer

Actually I don t like the GOTO command too  but it s in official Microsoft materials  and here are all allowed syntaxes  If the end point of the statement list of a switch section is reachable  a compile-time error occurs  This is known as the  quot no fall through quot  rule  The example switch  i    case 0     CaseZero       break  case 1     CaseOne       break  default     CaseOthers       break     is valid because no switch section has a reachable end point  Unlike C and C    execution of a switch section is not permitted to  quot fall through quot  to the next switch section  and the example switch  i    case 0     CaseZero    case 1     CaseZeroOrOne    default     CaseAny       results in a compile-time error  When execution of a switch section is to be followed by execution of another switch section  an explicit goto case or goto default statement must be used  switch  i    case 0     CaseZero       goto case 1  case 1     CaseZeroOrOne       goto default  default     CaseAny       break     Multiple labels are permitted in a switch-section  The example switch  i    case 0     CaseZero       break  case 1     CaseOne       break  case 2  default     CaseTwo       break     I believe in this particular case  the GOTO can be used  and it s actually the only way to fallthrough  Source

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I guess this has been already answered  However  I think that you can still mix both options in a syntactically better way by doing   switch  value        case 1  case 2  case 3                       Do Something         break      case 4  case 5  case 6              Do Something         break      default             Do Something         break

User · Answer

You can also have conditions that are completely different             bool isTrue   true               switch  isTrue                                case bool ifTrue when  ex Message Contains  quot not found quot                     case bool ifTrue when  thing number   123                   case bool ifTrue when  thing othernumber    456                       response respCode   5010                      break                  case bool ifTrue when  otherthing text    quot something else quot                        response respCode   5020                      break                  default                      response respCode   5000                      break

User · Answer

This syntax is from the Visual Basic Select   Case Statement  Dim number As Integer   8 Select Case number     Case 1 To 5         Debug WriteLine  quot Between 1 and 5  inclusive quot             The following is the only Case clause that evaluates to True      Case 6  7  8         Debug WriteLine  quot Between 6 and 8  inclusive quot       Case Is  lt  1         Debug WriteLine  quot Equal to 9 or 10 quot       Case Else         Debug WriteLine  quot Not between 1 and 10  inclusive quot   End Select  You cannot use this syntax in C    Instead  you must use the syntax from your first example

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The code below won t work   case 1   3   5     Not working do something   The only way to do this is   case 1  case 2  case 3     Do something break    The code you are looking for works in Visual Basic where you easily can put in ranges    in the none option of the switch statement or if else blocks convenient  I d suggest to  at very extreme point  make  dll with Visual Basic and import back to your C  project   Note  the switch equivalent in Visual Basic is Select Case

User · Answer

This syntax is from the Visual Basic Select   Case Statement  Dim number As Integer   8 Select Case number     Case 1 To 5         Debug WriteLine  quot Between 1 and 5  inclusive quot             The following is the only Case clause that evaluates to True      Case 6  7  8         Debug WriteLine  quot Between 6 and 8  inclusive quot       Case Is  lt  1         Debug WriteLine  quot Equal to 9 or 10 quot       Case Else         Debug WriteLine  quot Not between 1 and 10  inclusive quot   End Select  You cannot use this syntax in C    Instead  you must use the syntax from your first example

User · Answer

Just to add to the conversation  using  NET 4 6 2 I was also able to do the following  I tested the code and it did work for me   You can also do multiple  OR  statements  like below               switch  value                                case string a when a Contains  text1                           Do Something                     break                  case string b when b Contains  text3      b Contains  text4      b Contains  text5                           Do Something else                     break                  default                         Or do this by default                     break                  You can also check if it matches a value in an array               string   statuses      text3    text4    text5                 switch  value                                case string a when a Contains  text1                           Do Something                     break                  case string b when statuses Contains value                                                  Do Something else                     break                  default                         Or do this by default                     break

User · Answer

One lesser known facet of switch in C  is that it relies on the operator  and since it can be overriden you could have something like this    string s   foo     switch  s      case  abc           break    case  def           break

User · Answer

If you have a very big amount of strings  or any other type  case all doing the same thing  I recommend the use of a string list combined with the string Contains property   So if you have a big switch statement like so   switch  stringValue        case  cat       case  dog       case  string3               case   1000 more string      Too many string to write a case for all             Do something      case  a lonely case             Do something else                        You might want to replace it with an if statement like this      Define all the similar  case  string in a List List lt string gt  listString   new List lt string gt      cat    dog    string3     1000 more string       Use string Contains to find what you are looking for if  listString Contains stringValue            Do something    else          Then go back to a switch statement inside the else for the remaining cases if you really need to     This scale well for any number of string cases

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Another option would be to use a routine  If cases 1-3 all execute the same logic then wrap that logic in a routine and call it for each case  I know this doesn t actually get rid of the case statements  but it does implement good style and keep maintenance to a minimum        Edit  Added alternate implementation to match original question     Edit   switch  x       case 1        DoSomething          break     case 2        DoSomething          break     case 3        DoSomething          break            private void DoSomething                Alt  switch  x       case 1     case 2     case 3        DoSomething          break            private void DoSomething

User · Answer

One lesser known facet of switch in C  is that it relies on the operator  and since it can be overriden you could have something like this    string s   foo     switch  s      case  abc           break    case  def           break

User · Answer

An awful lot of work seems to have been put into finding ways to get one of C  least used syntaxes to somehow look better or work better   Personally I find the switch statement is seldom worth using   I would strongly suggest analyzing what data you are testing and the end results you are wanting     Let us say for example you want to quickly test values in a known range to see if they are prime numbers   You want to avoid having your code do the wasteful calculations and you can find a list of primes in the range you want online   You could use a massive switch statement to compare each value to known prime numbers     Or you could just create an array map of primes and get immediate results       bool   Primes   new bool             false  false  true  true  false  true  false              true  false  false  false  true  false  true          false false false true false true false       private void button1 Click object sender  EventArgs e            int Value   Convert ToInt32 textBox1 Text           if   Value  gt   0   amp  amp   Value  lt  Primes Length                 bool IsPrime   Primes Value               textBox2 Text   IsPrime ToString                      Maybe you want to see if a character in a string is hexadecimal   You could use an ungly and somewhat large switch statement   Or you could use either regular expressions to test the char or use the IndexOf function to search for the char in a string of known hexadecimal letters           private void textBox2 TextChanged object sender  EventArgs e            try               textBox1 Text     0123456789ABCDEFGabcdefg  IndexOf textBox2 Text 0    gt   0  ToString              catch                     Let us say you want to do one of 3 different actions depending on a value that will be the range of 1 to 24   I would suggest using a set of IF statements   And if that became too complex  Or the numbers were larger such as 5 different actions depending on a value in the range of 1 to 90  then use an enum to define the actions and create an array map of the enums   The value would then be used to index into the array map and get the enum of the action you want   Then use either a small set of IF statements or a very simple switch statement to process the resulting enum value   Also  the nice thing about an array map that converts a range of values into actions is that it can be easily changed by code   With hard wired code you can t easily change behaviour at runtime but with an array map it is easy

User · Answer

Actually I don t like the GOTO command too  but it s in official Microsoft materials  and here are all allowed syntaxes  If the end point of the statement list of a switch section is reachable  a compile-time error occurs  This is known as the  quot no fall through quot  rule  The example switch  i    case 0     CaseZero       break  case 1     CaseOne       break  default     CaseOthers       break     is valid because no switch section has a reachable end point  Unlike C and C    execution of a switch section is not permitted to  quot fall through quot  to the next switch section  and the example switch  i    case 0     CaseZero    case 1     CaseZeroOrOne    default     CaseAny       results in a compile-time error  When execution of a switch section is to be followed by execution of another switch section  an explicit goto case or goto default statement must be used  switch  i    case 0     CaseZero       goto case 1  case 1     CaseZeroOrOne       goto default  default     CaseAny       break     Multiple labels are permitted in a switch-section  The example switch  i    case 0     CaseZero       break  case 1     CaseOne       break  case 2  default     CaseTwo       break     I believe in this particular case  the GOTO can be used  and it s actually the only way to fallthrough  Source

User · Answer

This syntax is from the Visual Basic Select   Case Statement  Dim number As Integer   8 Select Case number     Case 1 To 5         Debug WriteLine  quot Between 1 and 5  inclusive quot             The following is the only Case clause that evaluates to True      Case 6  7  8         Debug WriteLine  quot Between 6 and 8  inclusive quot       Case Is  lt  1         Debug WriteLine  quot Equal to 9 or 10 quot       Case Else         Debug WriteLine  quot Not between 1 and 10  inclusive quot   End Select  You cannot use this syntax in C    Instead  you must use the syntax from your first example

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Here is the complete C  7 solution     switch  value       case var s when new     1 2 3   Contains s            Do something       break     case var s when new     4 5 6   Contains s            Do something       break     default           Do the default       break      It works with strings too     switch  mystring       case var s when new      Alpha   Beta   Gamma    Contains s            Do something       break

User · Answer

There is no syntax in C   nor C  for the second method you mentioned    There s nothing wrong with your first method   If however you have very big ranges  just use a series of if statements

User · Answer

There is no syntax in C   nor C  for the second method you mentioned    There s nothing wrong with your first method   If however you have very big ranges  just use a series of if statements

User · Answer

I think this one is better in C  7 or above   switch  value        case var s when new     1 2   Contains s          Do something      break       default         Do the default     break       You can also check Range in C  switch case  Switch case  can I use a range instead of a one number Or if you want to understand basics of  C  switch case

User · Answer

Another option would be to use a routine  If cases 1-3 all execute the same logic then wrap that logic in a routine and call it for each case  I know this doesn t actually get rid of the case statements  but it does implement good style and keep maintenance to a minimum        Edit  Added alternate implementation to match original question     Edit   switch  x       case 1        DoSomething          break     case 2        DoSomething          break     case 3        DoSomething          break            private void DoSomething                Alt  switch  x       case 1     case 2     case 3        DoSomething          break            private void DoSomething

User · Answer

I guess this has been already answered  However  I think that you can still mix both options in a syntactically better way by doing   switch  value        case 1  case 2  case 3                       Do Something         break      case 4  case 5  case 6              Do Something         break      default             Do Something         break

User · Answer

Just to add to the conversation  using  NET 4 6 2 I was also able to do the following  I tested the code and it did work for me   You can also do multiple  OR  statements  like below               switch  value                                case string a when a Contains  text1                           Do Something                     break                  case string b when b Contains  text3      b Contains  text4      b Contains  text5                           Do Something else                     break                  default                         Or do this by default                     break                  You can also check if it matches a value in an array               string   statuses      text3    text4    text5                 switch  value                                case string a when a Contains  text1                           Do Something                     break                  case string b when statuses Contains value                                                  Do Something else                     break                  default                         Or do this by default                     break

User · Answer

With C 9 came the Relational Pattern Matching  This allows us to do  switch  value        case 1 or 2 or 3           Do stuff       break      case 4 or 5 or 6           Do stuff       break      default             Do stuff         break     In deep tutorial of Relational Patter in C 9 Pattern-matching changes for C  9 0  Relational patterns permit the programmer to express that an input value must satisfy a relational constraint when compared to a constant value

User · Answer

If you have a very big amount of strings  or any other type  case all doing the same thing  I recommend the use of a string list combined with the string Contains property   So if you have a big switch statement like so   switch  stringValue        case  cat       case  dog       case  string3               case   1000 more string      Too many string to write a case for all             Do something      case  a lonely case             Do something else                        You might want to replace it with an if statement like this      Define all the similar  case  string in a List List lt string gt  listString   new List lt string gt      cat    dog    string3     1000 more string       Use string Contains to find what you are looking for if  listString Contains stringValue            Do something    else          Then go back to a switch statement inside the else for the remaining cases if you really need to     This scale well for any number of string cases

User · Answer

gcc implements an extension to the C language to support sequential ranges   switch  value       case 1   3          Do Something       break     case 4   6          Do Something       break     default          Do the Default       break      Edit  Just noticed the C  tag on the question  so presumably a gcc answer doesn t help

User · Answer

gcc implements an extension to the C language to support sequential ranges   switch  value       case 1   3          Do Something       break     case 4   6          Do Something       break     default          Do the Default       break      Edit  Just noticed the C  tag on the question  so presumably a gcc answer doesn t help

User · Answer

Another option would be to use a routine  If cases 1-3 all execute the same logic then wrap that logic in a routine and call it for each case  I know this doesn t actually get rid of the case statements  but it does implement good style and keep maintenance to a minimum        Edit  Added alternate implementation to match original question     Edit   switch  x       case 1        DoSomething          break     case 2        DoSomething          break     case 3        DoSomething          break            private void DoSomething                Alt  switch  x       case 1     case 2     case 3        DoSomething          break            private void DoSomething

User · Answer

NET Framework 3 5 has got ranges   Enumerable Range from MSDN  you can use it with  contains  and the IF statement  since like someone said the SWITCH statement uses the      operator   Here an example   int c   2  if Enumerable Range 0 10  Contains c       DoThing    else if Enumerable Range 11 20  Contains c       DoAnotherThing      But I think we can have more fun  since you won t need the return values and this action doesn t take parameters  you can easily use actions   public static void MySwitchWithEnumerable int switchcase  int startNumber  int endNumber  Action action        if Enumerable Range startNumber  endNumber  Contains switchcase           action        The old example with this new method   MySwitchWithEnumerable c  0  10  DoThing   MySwitchWithEnumerable c  10  20  DoAnotherThing     Since you are passing actions  not values  you should omit the parenthesis  it s very important  If you need function with arguments  just change the type of Action to Action lt ParameterType gt   If you need return values  use Func lt ParameterType  ReturnType gt    In C  3 0 there is no easy Partial Application to encapsulate the fact the the case parameter is the same  but you create a little helper method  a bit verbose  tho    public static void MySwitchWithEnumerable int startNumber  int endNumber  Action action        MySwitchWithEnumerable 3  startNumber  endNumber  action        Here an example of how new functional imported statement are IMHO more powerful and elegant than the old imperative one

User · Answer

gcc implements an extension to the C language to support sequential ranges   switch  value       case 1   3          Do Something       break     case 4   6          Do Something       break     default          Do the Default       break      Edit  Just noticed the C  tag on the question  so presumably a gcc answer doesn t help

User · Answer

The code below won t work   case 1   3   5     Not working do something   The only way to do this is   case 1  case 2  case 3     Do something break    The code you are looking for works in Visual Basic where you easily can put in ranges    in the none option of the switch statement or if else blocks convenient  I d suggest to  at very extreme point  make  dll with Visual Basic and import back to your C  project   Note  the switch equivalent in Visual Basic is Select Case

User · Answer

For this  you would use a goto statement   Such as       switch value       case 1          goto case 3      case 2          goto case 3      case 3          DoCase123          This would work too  but I m not sure if it s slower     case 4          goto case 5      case 5          goto case 6      case 6          goto case 7      case 7          DoCase4567

User · Answer

NET Framework 3 5 has got ranges   Enumerable Range from MSDN  you can use it with  contains  and the IF statement  since like someone said the SWITCH statement uses the      operator   Here an example   int c   2  if Enumerable Range 0 10  Contains c       DoThing    else if Enumerable Range 11 20  Contains c       DoAnotherThing      But I think we can have more fun  since you won t need the return values and this action doesn t take parameters  you can easily use actions   public static void MySwitchWithEnumerable int switchcase  int startNumber  int endNumber  Action action        if Enumerable Range startNumber  endNumber  Contains switchcase           action        The old example with this new method   MySwitchWithEnumerable c  0  10  DoThing   MySwitchWithEnumerable c  10  20  DoAnotherThing     Since you are passing actions  not values  you should omit the parenthesis  it s very important  If you need function with arguments  just change the type of Action to Action lt ParameterType gt   If you need return values  use Func lt ParameterType  ReturnType gt    In C  3 0 there is no easy Partial Application to encapsulate the fact the the case parameter is the same  but you create a little helper method  a bit verbose  tho    public static void MySwitchWithEnumerable int startNumber  int endNumber  Action action        MySwitchWithEnumerable 3  startNumber  endNumber  action        Here an example of how new functional imported statement are IMHO more powerful and elegant than the old imperative one

User · Answer

NET Framework 3 5 has got ranges   Enumerable Range from MSDN  you can use it with  contains  and the IF statement  since like someone said the SWITCH statement uses the      operator   Here an example   int c   2  if Enumerable Range 0 10  Contains c       DoThing    else if Enumerable Range 11 20  Contains c       DoAnotherThing      But I think we can have more fun  since you won t need the return values and this action doesn t take parameters  you can easily use actions   public static void MySwitchWithEnumerable int switchcase  int startNumber  int endNumber  Action action        if Enumerable Range startNumber  endNumber  Contains switchcase           action        The old example with this new method   MySwitchWithEnumerable c  0  10  DoThing   MySwitchWithEnumerable c  10  20  DoAnotherThing     Since you are passing actions  not values  you should omit the parenthesis  it s very important  If you need function with arguments  just change the type of Action to Action lt ParameterType gt   If you need return values  use Func lt ParameterType  ReturnType gt    In C  3 0 there is no easy Partial Application to encapsulate the fact the the case parameter is the same  but you create a little helper method  a bit verbose  tho    public static void MySwitchWithEnumerable int startNumber  int endNumber  Action action        MySwitchWithEnumerable 3  startNumber  endNumber  action        Here an example of how new functional imported statement are IMHO more powerful and elegant than the old imperative one

User · Answer

Here is the complete C  7 solution     switch  value       case var s when new     1 2 3   Contains s            Do something       break     case var s when new     4 5 6   Contains s            Do something       break     default           Do the default       break      It works with strings too     switch  mystring       case var s when new      Alpha   Beta   Gamma    Contains s            Do something       break

User · Answer

One lesser known facet of switch in C  is that it relies on the operator  and since it can be overriden you could have something like this    string s   foo     switch  s      case  abc           break    case  def           break

User · Answer

This syntax is from the Visual Basic Select   Case Statement  Dim number As Integer   8 Select Case number     Case 1 To 5         Debug WriteLine  quot Between 1 and 5  inclusive quot             The following is the only Case clause that evaluates to True      Case 6  7  8         Debug WriteLine  quot Between 6 and 8  inclusive quot       Case Is  lt  1         Debug WriteLine  quot Equal to 9 or 10 quot       Case Else         Debug WriteLine  quot Not between 1 and 10  inclusive quot   End Select  You cannot use this syntax in C    Instead  you must use the syntax from your first example

User · Answer

In C  7 we now have Pattern Matching so you can do something like   switch  age      case 50      ageBlock    the big five-oh       break    case var testAge when  new List lt int gt            80  81  82  83  84  85  86  87  88  89    Contains testAge       ageBlock    octogenarian       break    case var testAge when   testAge  gt   90   amp   testAge  lt   99        ageBlock    nonagenarian       break    case var testAge when  testAge  gt   100       ageBlock    centenarian       break    default      ageBlock    just old       break

User · Answer

I think this one is better in C  7 or above   switch  value        case var s when new     1 2   Contains s          Do something      break       default         Do the default     break       You can also check Range in C  switch case  Switch case  can I use a range instead of a one number Or if you want to understand basics of  C  switch case

User · Answer

NET Framework 3 5 has got ranges   Enumerable Range from MSDN  you can use it with  contains  and the IF statement  since like someone said the SWITCH statement uses the      operator   Here an example   int c   2  if Enumerable Range 0 10  Contains c       DoThing    else if Enumerable Range 11 20  Contains c       DoAnotherThing      But I think we can have more fun  since you won t need the return values and this action doesn t take parameters  you can easily use actions   public static void MySwitchWithEnumerable int switchcase  int startNumber  int endNumber  Action action        if Enumerable Range startNumber  endNumber  Contains switchcase           action        The old example with this new method   MySwitchWithEnumerable c  0  10  DoThing   MySwitchWithEnumerable c  10  20  DoAnotherThing     Since you are passing actions  not values  you should omit the parenthesis  it s very important  If you need function with arguments  just change the type of Action to Action lt ParameterType gt   If you need return values  use Func lt ParameterType  ReturnType gt    In C  3 0 there is no easy Partial Application to encapsulate the fact the the case parameter is the same  but you create a little helper method  a bit verbose  tho    public static void MySwitchWithEnumerable int startNumber  int endNumber  Action action        MySwitchWithEnumerable 3  startNumber  endNumber  action        Here an example of how new functional imported statement are IMHO more powerful and elegant than the old imperative one

User · Answer

There is no syntax in C   nor C  for the second method you mentioned    There s nothing wrong with your first method   If however you have very big ranges  just use a series of if statements

User · Answer

In C  7  available by default in Visual Studio 2017  NET Framework 4 6 2   range-based switching is now possible with the switch statement and would help with the OP s problem   Example   int i   5   switch  i        case int n when  n  gt   7           Console WriteLine   I am 7 or above   n             break       case int n when  n  gt   4  amp  amp  n  lt   6            Console WriteLine   I am between 4 and 6   n             break       case int n when  n  lt   3           Console WriteLine   I am 3 or less   n             break        Output  I am between 4 and 6  5   Notes    The parentheses   and   are not required in the when condition  but are used in this example to highlight the comparison s    var may also be used in lieu of int  For example  case var n when n  gt   7

User · Answer

For this  you would use a goto statement   Such as       switch value       case 1          goto case 3      case 2          goto case 3      case 3          DoCase123          This would work too  but I m not sure if it s slower     case 4          goto case 5      case 5          goto case 6      case 6          goto case 7      case 7          DoCase4567

User · Answer

In C  7 we now have Pattern Matching so you can do something like   switch  age      case 50      ageBlock    the big five-oh       break    case var testAge when  new List lt int gt            80  81  82  83  84  85  86  87  88  89    Contains testAge       ageBlock    octogenarian       break    case var testAge when   testAge  gt   90   amp   testAge  lt   99        ageBlock    nonagenarian       break    case var testAge when  testAge  gt   100       ageBlock    centenarian       break    default      ageBlock    just old       break

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You can leave out the newline which gives you   case 1  case 2  case 3     break    but I consider that bad style

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You can also have conditions that are completely different             bool isTrue   true               switch  isTrue                                case bool ifTrue when  ex Message Contains  quot not found quot                     case bool ifTrue when  thing number   123                   case bool ifTrue when  thing othernumber    456                       response respCode   5010                      break                  case bool ifTrue when  otherthing text    quot something else quot                        response respCode   5020                      break                  default                      response respCode   5000                      break

User · Answer

There is no syntax in C   nor C  for the second method you mentioned    There s nothing wrong with your first method   If however you have very big ranges  just use a series of if statements

User · Answer

You can leave out the newline which gives you   case 1  case 2  case 3     break    but I consider that bad style

User · Answer

You can leave out the newline which gives you   case 1  case 2  case 3     break    but I consider that bad style

User · Answer

gcc implements an extension to the C language to support sequential ranges   switch  value       case 1   3          Do Something       break     case 4   6          Do Something       break     default          Do the Default       break      Edit  Just noticed the C  tag on the question  so presumably a gcc answer doesn t help

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In C  7  available by default in Visual Studio 2017  NET Framework 4 6 2   range-based switching is now possible with the switch statement and would help with the OP s problem   Example   int i   5   switch  i        case int n when  n  gt   7           Console WriteLine   I am 7 or above   n             break       case int n when  n  gt   4  amp  amp  n  lt   6            Console WriteLine   I am between 4 and 6   n             break       case int n when  n  lt   3           Console WriteLine   I am 3 or less   n             break        Output  I am between 4 and 6  5   Notes    The parentheses   and   are not required in the when condition  but are used in this example to highlight the comparison s    var may also be used in lieu of int  For example  case var n when n  gt   7

User · Answer

You can leave out the newline which gives you   case 1  case 2  case 3     break    but I consider that bad style

User · Answer

Another option would be to use a routine  If cases 1-3 all execute the same logic then wrap that logic in a routine and call it for each case  I know this doesn t actually get rid of the case statements  but it does implement good style and keep maintenance to a minimum        Edit  Added alternate implementation to match original question     Edit   switch  x       case 1        DoSomething          break     case 2        DoSomething          break     case 3        DoSomething          break            private void DoSomething                Alt  switch  x       case 1     case 2     case 3        DoSomething          break            private void DoSomething

User · Answer

With C 9 came the Relational Pattern Matching  This allows us to do  switch  value        case 1 or 2 or 3           Do stuff       break      case 4 or 5 or 6           Do stuff       break      default             Do stuff         break     In deep tutorial of Relational Patter in C 9 Pattern-matching changes for C  9 0  Relational patterns permit the programmer to express that an input value must satisfy a relational constraint when compared to a constant value

User · Answer

An awful lot of work seems to have been put into finding ways to get one of C  least used syntaxes to somehow look better or work better   Personally I find the switch statement is seldom worth using   I would strongly suggest analyzing what data you are testing and the end results you are wanting     Let us say for example you want to quickly test values in a known range to see if they are prime numbers   You want to avoid having your code do the wasteful calculations and you can find a list of primes in the range you want online   You could use a massive switch statement to compare each value to known prime numbers     Or you could just create an array map of primes and get immediate results       bool   Primes   new bool             false  false  true  true  false  true  false              true  false  false  false  true  false  true          false false false true false true false       private void button1 Click object sender  EventArgs e            int Value   Convert ToInt32 textBox1 Text           if   Value  gt   0   amp  amp   Value  lt  Primes Length                 bool IsPrime   Primes Value               textBox2 Text   IsPrime ToString                      Maybe you want to see if a character in a string is hexadecimal   You could use an ungly and somewhat large switch statement   Or you could use either regular expressions to test the char or use the IndexOf function to search for the char in a string of known hexadecimal letters           private void textBox2 TextChanged object sender  EventArgs e            try               textBox1 Text     0123456789ABCDEFGabcdefg  IndexOf textBox2 Text 0    gt   0  ToString              catch                     Let us say you want to do one of 3 different actions depending on a value that will be the range of 1 to 24   I would suggest using a set of IF statements   And if that became too complex  Or the numbers were larger such as 5 different actions depending on a value in the range of 1 to 90  then use an enum to define the actions and create an array map of the enums   The value would then be used to index into the array map and get the enum of the action you want   Then use either a small set of IF statements or a very simple switch statement to process the resulting enum value   Also  the nice thing about an array map that converts a range of values into actions is that it can be easily changed by code   With hard wired code you can t easily change behaviour at runtime but with an array map it is easy

[c#] Multiple cases in switch statement

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