( Output of Dada compiler ) ( To execute type: 1 LOAD HAILSTONE ) ;S FORTH DEFINITIONS DECIMAL 1 CONSTANT TRUE 0 CONSTANT FALSE : NEGATE MINUS ; : NOT 0= ; : <> = NOT ; : >= < NOT ; : <= > NOT ; : READ KEY DUP 45 = IF TRUE SWAP EMIT KEY ELSE FALSE SWAP THEN 0 SWAP BEGIN DUP 13 = NOT WHILE DUP 48 < OVER 57 > OR IF DROP 7 EMIT ELSE DUP EMIT 48 - SWAP 10 * + THEN KEY REPEAT DROP SWAP IF NEGATE THEN SWAP ! ; : WRITE @ . CR ; --> 0 VARIABLE N 0 VARIABLE ODD : CHECKODD N @ 2 MOD 0 = IF FALSE ODD ! ELSE TRUE ODD ! THEN ; : DOWNSTEP N @ 2 / N ! ; : UPSTEP 3 N @ * 1 + N ! ; : NEXTTERM CHECKODD ODD @ IF UPSTEP ELSE DOWNSTEP THEN ; : HAILSTONE N READ BEGIN N @ 1 > WHILE N WRITE NEXTTERM REPEAT ; ;S
