Section 7: Program Editing

87

Insertions and Deletions

After an insertion, the display will show the instruction you just added. After a deletion, the display will show the line prior to the deleted (now nonexistent) one.

If all space available in memory is occupied, the calculator will not accept any program instruction insertions and Error 4 will be displayed.

Initializing Calculator Status

The contents of storage registers and the status of calculator settings will affect a program if the program uses those registers or depends on a certain status setting. If the current status is incorrect for the program being run, you will get incorrect results. Therefore, it is wise to clear registers and set relevant modes either just prior to running a program or within the program itself. A self-initializing program is more mistake-proof—but it also uses more program lines.

Calculator-initializing functions are: ´ CLEAR ∑, ´ CLEAR M, ´ CLEAR Q, D, R, g, F, and ".

Problems

It is good programming technique to avoid using identical program labels. (This shouldn't be hard, since the HP-15C provides 25 different labels.) To ensure against duplication of labels, you can clear program memory first.

1.The following program is used by the manager of a savings and loan

company to compute the future values of savings accounts according to the formula FV = PV (l + i)n, where FV is future value, PV is present value, i is the periodic interest rate, and n is the number of periods. Enter PV first (into the Y-register) and n second (into the X- register) before executing the program. Given is an annual interest rate of 7.5% (so i = 0.075).

Page 87
Image 87
HP 15c Scientific manual Insertions and Deletions, Initializing Calculator Status