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PROGRAM enum;
 
{ ENUM.PAS demonstrates procedures and functions used with
  enumerated types, including:
 
      First    Last    Ord    Pred    Succ
}
 
TYPE
    planets_t = (mercury, venus, earth, mars, jupiter, saturn, uranus,
                 neptune, pluto);
    p_names   = ARRAY[planets_t] OF STRING[7];
 
CONST
    program_name = 'ENUM ';
    program_desc = 'demonstrates enumerated types.';
    planet_str : p_names = ('Mercury', 'Venus', 'Earth', 'Mars',
                'Jupiter', 'Saturn', 'Uranus', 'Neptune', 'Pluto');
 
VAR
    planet :  planets_t;
 
BEGIN
 
    Writeln( program_name, program_desc );
    Writeln;
    Writeln( 'The planet nearest the sun is ',
              planet_str[First( planets_t )], '.');
    Writeln( 'The next planet is ',
              planet_str[Succ( First( planets_t ) )], '.' );
 
    { Note that ORD of a type starts at 0; hence we add one. }
    Writeln( 'Our planet is the ', Ord( earth ) + 1,
             'rd planet from the sun.');
    Writeln( planet_str[Pred( earth )], ' and ',
             planet_str[Succ( earth )], ' are on either side of Earth.');
    Writeln( 'Usually, the next-to-last planet from the sun is ',
             planet_str[Pred( Last( planets_t ) )], '.');
    Writeln( 'Usually, the farthest planet from the sun is ',
             planet_str[Last( planets_t )], '.');
 
END.