HP 12C Financial 12C The Key in ALG Mode, The History Stack in ALG Mode, not, new, Display, executed, Keystrokes, (ALG mode), digit entry, Appendix B: Algebraic Mode (ALG)

	Appendix B: Algebraic Mode (ALG) 239
Keystrokes	Display
(ALG mode)
OO	0.00	Clears any pending operations.
456-75z	381.00
18.5§	20.59
68z	1,400.43
1.9}	737.07

The Key in ALG Mode

LAST X in ALG mode is not used in this book. It is the one function that is quite different in ALG and RPN modes. Refer to page 234 for the list of 23 different key presses that cause the displayed X-register to be copied into the LAST X register in RPN mode. In ALG mode, those key presses do not cause a refresh of the LAST X register. Instead, the displayed number is copied into the LAST X register when a new calculation commences either with digit entry (i.e., when one of the digits 0-9, the decimal point, or Æ is pressed) or with gF itself, but not when a number is recalled using :.

When gFis actually executed in ALG mode, it simply swaps the value in the X-register with the value in LAST X. Therefore, in ALG mode, it never lifts the stack and in general, it changes the value in LAST X. However, in RPN mode, gFalways lifts the stack and leaves the value in LAST X unchanged.

In general, LAST X in ALG mode is only useful in programs, where it can often be used instead of a numbered storage register, as it persists unchanged at least until digit entry or gF. There is an example of its use in the Combinations program in the hp 12c platinum Solutions Handbook.

The History Stack in ALG Mode

In ALG mode, the stack holds a “history” of 4 completed results. These results may be rearranged using dand ~in the same way as described on page 230, for RPN mode.

Note that once a two-numbered function (such as +, -, §, zor q) has had the second argument entered, the two arguments cannot then be swapped using

~because when the second argument is entered it replaces the first, which is removed from the stack. So, if you wish to do 25.83 -144.25, but then realize you meant to do 144.25 - 25.83, the way to correct this is to proceed and do }Þ. All ~ will do at this point is replace the 144.25 with whatever was displayed before the 25.83 was entered, and the first argument remains unchanged.

File name: hp 12c pt_user's guide_English_HDPMF123E27	Page: 239 of 275
Printed Date: 2005/8/1	Dimension: 14.8 cm x 21 cm