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Subrange Types

• An ordered, contiguous subsequence of another ordinal type

• Design Issue: How can they be used?

• Examples:
  • Pascal--subrange types behave as their parent types; can be used as for variables and array indices

        type pos = 0 .. MAXINT;
    

  • Ada--subtypes are not new types, just constrained existing types (so they are compatible); can be used as in Pascal, plus case constants

        subtype Pos_Type is
            Integer range 0 ..Integer'Last;