//----------------------------------------------------------------------
//  SPECIFICATION FILE (cset.h)
//  This module exports a character set ADT.  A more general module
//  would include additional set operations.
//----------------------------------------------------------------------
#ifndef cset_h
#define cset_h

#include "bool.h"

class CharSet {
    // ABSTRACTLY: a collection of ASCII characters
public:
    Boolean IsEmpty() const;
        // POST:  FCTVAL == (collection is empty)

    Boolean IsFull() const;
        // POST: FCTVAL == true if no more
        // items can be stored, false otherwise

    void Insert( char ch );
        // PRE: the collection isn't full
        // MODIFIES: self
        // POST: self == self<entry> union {i}

    void Delete( char ch );
        // MODIFIES: self
        // POST: self == self<entry> - i

    Boolean IsElt( char ch ) const;
        // POST: FCTVAL == (i is in collection)

    CharSet Intersect( CharSet set2 ) const;
        // POST: FCTVAL == is a collection of
        // the elements in both self and set2

    CharSet Union( CharSet set2 ) const;
        // POST: FCTVAL == is a collection of
        // the elements in either self or set2

    CharSet();
        // MODIFIES: self
        // POST: the collection is empty

#include "cset.pri"
};
#endif