( Copyright PPC Paris 1986 )
: FRC
        X=0?   IF   ." 0" EXIT   THEN
       0 0. X<>Y X<Y?   IF   1-   THEN   FABS
       0 1. X>Y? X<>Y   IF   1+   1/X   THEN
    0 BEGIN
          1+ DUP   FENTER   ITOF F* FENTER FP FABS
         .000001 X>Y?   RDN .999999 X<Y?   +   RUP
          UNTIL
    RUP .1  F+ IP   ROT   IF   ." -"   THEN   SWAP
    IF   .   ." /"   F.
     ELSE   F.   ." /"   .
     THEN ;


: FRC
        X=0?   IF   ." 0" EXIT   THEN
       0 0. X<>Y X<Y?   IF   1-   THEN   FABS
       0 1. X>Y? X<>Y   IF   1+   1/X   THEN
    0 BEGIN
          1+ DUP   FENTER   ITOF F* FENTER FP FABS
         .000001 X>Y?   RDN .999999 X<Y?   +   RUP
          UNTIL
    RUP .1  F+ IP   ROT   IF   ." -"   THEN   SWAP
    IF   .   ." /"   F.
     ELSE   F.   ." /"   .
     THEN ;