Most mind-blowing program for your favorite calculator

[Thomas Klemm]

(07-02-2022 09:24 AM)Pälzer Wrote:  further question 1:
is there a thread known which had the topic HP 17b/HP19b + Solver with explanations ?
my search did not find anything, but I may have used the wrong search words.

further question 2.
is there an equation with loop that is "shorter" that I can look at

These two just came to my mind:

• checkdigit calculation for HP-17b
• number base conversion for hp17b/17bii
  

Meanwhile I also found these:

• an elegant algorithm related to Ulam's spiral
• [17B, 18C, 19B, 27S] Solver GET/LET explained
  

In the attached PDF of the 2nd link on page 4 you can find a description How LET and GET Change an Equation.
This let's us use the following formula iteratively to calculate the GCD:

B=0×(L(R:MOD(A:G(B)))+L(A:G(B))+G(R)

After verifying the equation you should end up with a menu like this:

[  B  ][  A  ]

After entering A and B just keep hitting the B key until the result is 0.
The GCD can then be found in A.

Example

112 A
63 B

B
CALCULATING...
B=49

B
CALCULATING...
B=14

B
CALCULATING...
B=7

B
CALCULATING...
B=0

RCL A
A=7

HTH