gcc.info: Case Ranges

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Case Ranges

   You can specify a range of consecutive values in a single `case'
label, like this:
     case LOW ... HIGH:
This has the same effect as the proper number of individual `case'
labels, one for each integer value from LOW to HIGH, inclusive.
   This feature is especially useful for ranges of ASCII character
codes:
     case 'A' ... 'Z':
   *Be careful:* Write spaces around the `...', for otherwise it may be
parsed wrong when you use it with integer values.  For example, write
this:
     case 1 ... 5:
rather than this:
     case 1...5: