Clear Stack (CLST, CLSTK) and LastX

[PANAMATIK]

(03-12-2015 07:49 PM)Thomas Radtke Wrote:  

(03-12-2015 07:29 PM)MarkHaysHarris777 Wrote:  LASTX is intended for interactive error correction [...]

Please see the manual about the use of last_x (35s manual, chapter 2-8):

2. Resuing a number in a calculation

You should be able to do this in a program also. It's just another bug, unfortunately.

LastX was invented with the second calculator ever the HP-45. Here is what the manual says:

Quote:The last input argument of a calculation is automatically stored in the
Last x register when a function is executed. This feature provides a
handy error correction device (see page 12 for examples)-as well as a
facility for reusing the same argument in multiple calculations-since
it allows recall of the argument by pressing f LastX. The register
is cleared only when the calculator is turned off or when a new argument
replaces (or overwrites) the previous one.

At the very beginning the reusing of the same number was mentioned.

In the HP-55 manual, the second programmable caculator, this is mentioned even before talking about input error correction.

Quote:LAST X
In addition to the four stack registers and the 20 data storage
registers, an additional register, the LAST X register, is provided
for your convenience. The last displayed number before
a calculation is automatically stored here. To recall the last
displayed number, simply press f LastX.

To Avoid Reentering Numbers
The LAST X register is useful in calculations where a number
occurs more than once.

Bernhard