PROGRAM setranges6(output);
        { Written by: Mirsad Todorovac Nov 2001; copying by GPL.
        ------------------------------------------------------------
        Stresses setrange construction and subtraction; checks if there's
        all IN SET what we haven't subtracted; and whether anything we've
	subtracted remained mistakenly IN SET.
        lasts few seconds where I've tested it.}
CONST maxN = 255;
VAR   seta, setb, setc: SET OF 0..maxN value [0..maxN];
      i, j, len: Cardinal;
      start, endr: 0 .. maxN;
      extra: Boolean = false;
      missing: Boolean = false;
      extI, extS, extE, misI, misS, misE: 0..maxN;

BEGIN

    {Test whether the set was initialized properly is mirsad03.pas}

    FOR len:= 1 TO maxN+1 DO
      FOR start:= 0 TO maxN-len+1 DO
	BEGIN
	  endr := start+len-1;
	  {writeln('constr. range = ', start, ',', endr);}
	  setb := seta - [start .. endr];
	  FOR i:= 0 TO maxN DO
	    BEGIN
	       {It's sufficient for one example to fail to have found a bug!}
	      IF (NOT extra AND (i>=start) AND (i<=endr) AND (i IN setb)) THEN
		BEGIN
		  extra := true;
		  extI := i;
		  extS := start;
		  extE := endr;
		END;
	      IF (NOT missing AND((i<start) OR (i>endr))AND NOT(i IN setb)) THEN
		BEGIN
		  missing := true;
		  misI := i;
		  misS := start;
		  misE := endr;
	 	END
	    END
	END;

    IF (NOT extra AND NOT missing) THEN
	writeln('OK')
    ELSE
      BEGIN
       write('Failed:');
       IF (extra) THEN
	write(' extra: ',extI,' IN [',0,'..',maxN,']-[',extS,'..',extE,']');
       IF (missing) THEN
	write(' miss: ',misI,' NOT IN [',0,'..',maxN,']-[',misS,'..',misE,']');
       writeln;
      END;
								
END.