RosettaCodeData/Task/Hailstone-sequence/ERRE/hailstone-sequence.erre

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PROGRAM ULAM
!$DOUBLE
PROCEDURE HAILSTONE(X,PRT%->COUNT)
COUNT=1
IF PRT% THEN PRINT(X,) END IF
REPEAT
IF X/2<>INT(X/2) THEN
X=X*3+1
ELSE
X=X/2
END IF
IF PRT% THEN PRINT(X,) END IF
COUNT=COUNT+1
UNTIL X=1
IF PRT% THEN PRINT END IF
END PROCEDURE
BEGIN
HAILSTONE(27,TRUE->COUNT)
PRINT("Sequence length for 27:";COUNT)
MAX_COUNT=2
NMAX=2
FOR I=3 TO 100000 DO
HAILSTONE(I,FALSE->COUNT)
IF COUNT>MAX_COUNT THEN NMAX=I MAX_COUNT=COUNT END IF
END FOR
PRINT("Max. number is";NMAX;" with";MAX_COUNT;"elements")
END PROGRAM