HP 50g: Neighbour Function (Dedekind Cut) Programme Challenge

[Werner]

I created this when Joe first mentioned the NEIGHBOR function.
It returns the next number larger than x=s*m*10^n

Basically, if x=0, return 1e-499
elsif s*m=-1, return (s.m + 1e-12)*10^n
else return (s.m + 1e-11)*10^n

Code:

\<<
  IF DUP
  THEN DUP XPON ALOG
  ELSE 1E-488 END
  SWAP OVER /     @ 10^n s*m
  DUP -1 \=/ 6 - 6 - ALOG + *
\>>

If I call this program NXT, then NEIGHBOR as defined in the 71 would be

Code:

\<< IF OVER < THEN +/- NXT +/- ELSE NXT END \>>

Cheers, Werner