HP 12C Financial calculator - Manual (Page 98)

98 Section 8: Programming Basics
File name: hp 12c_user's guide_English_HDPMBF12E44 Page: 98 of 209
Printered Date: 2005/7/29 Dimension: 14.8 cm x 21 cm
Example: Create a program that calculates the entries in the AMOUNT, TAX,
and TOTAL columns for each item on the jewelry distributor’s invoice shown on the
next page, and also calculates the total in each of these columns for all items on
the invoice. Assume the sales tax is 6
3 /
4
%.
To conserve lines of program memory, instead of keying in the tax rate before the
b instruction we’ll store it in register R
0
and recall it before the b instruction.
Before storing the program in program memory, we’ll calculate the required
amounts for the first item on the invoice manually. The keystroke sequence will use
storage register arithmetic (described on page 24) in registers R
1
, R
2
, and R
3
to
calculate the column sums. Since these registers are cleared when fCLEAR² is
pressed, we’ll press those keys before beginning the manual calculation — and
also later, before running the program — to ensure that the column sums are
“initialized” to zero. (Pressing fCLEARH would clear registers R
1
through R
3
,
but would also clear R
0
, which will contain the tax rate.)