HP-42S - How do I round a number?

[Albert Chan]

(03-22-2021 05:03 AM)Werner Wrote:  In the same vein, SCI 03 rounding: (which, incidentally, also fails for 0.9999.. ;-)

Code:

1E8
RCLx ST Y
+
LASTX
-

Free42, use 1E30

A more robust way is with Veltkamp’s splitting, algorithm 3
On various ways to split a floating-point number

C = 1E30 + 1      // Free42-Decimal, SCI 03 (*)
Y = C*X
Z = X-Y+Y          // Z has 34-30 = 4 sig. digits

(*) not quite: SCI-03 does half-way away-from-zero, Z does banker's rounding.