HP HP-20S - Stepping through Programs

Inserting program lines:
1. Enter Program mode.
2. Position the pointer to the line before where you want to add
lines.
3. Enter the new lines. They are inserted after the displayed line.
Succeeding lines are automatically renumbered.
4. To exit Program mode, press (¥4 [PRGM].
For example, if you want to insert several new lines between lines 04
and 05 of a program, you first display line 04, then enter the instruc-
tions. Subsequent program lines, starting with the original line 05, are
moved down and renumbered accordingly.
Stepping Through Programs
You can test programs by stepping through them. The program exe-
cutes one line at a time as you step through it. The result is displayed
after each program line is executed, so you can verify the progress of
calculations. To execute a program one line at a time:
1. Exit Program mode.
2. Position the pointer where you want to begin.
3. Enter data in the display, if necessary.
4. Press (\], then press and hold [v]. This displays the current
program line. When you release [¥], the line is executed. The
result of that execution is then displayed, and the program
pointer moves to the next line.
5. Repeat step 4 until you find an error or reach the end of the
program.
To move to the preceding line, you can press (¥y] (a]. No execution
occurs.
Example: Step through the execution of the program labeled A. Use
a diameter of 5 for the test data. Check that the PRGM annunciator is
off before you start.
72 6: Programming