Section 7: Program Editing

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The Back Step () Instruction. To move one line backwards in program memory, press (back step) in Program or Run mode. This function is not programmable. will scroll (with the key held down) in Program mode. Program instructions are not executed.

Deleting Program Lines

Deletions of program instructions are made with (back arrow) in Program mode. Move to the line you want to delete, then press . Any remaining following lines will be renumbered to stay in sequence.

Pressing in Run mode does not affect program memory, but is used for display clearing. (Refer to page 21.)

Inserting Program Lines

Additions to a program are made by moving to the line preceding the point of insertion. Any instruction you key in will be added following the line currently in the display. To alter an instruction, first delete it, then add the new version.

Examples

Let's refer back to the can volume program on page 71 in section 6 and make a few changes in the instructions. (The can program as listed below is assumed to be in memory starting on line 001.)

Deletions: If we don't need the summed base area, volume, and surface area values, we can delete the storage register additions (lines 007, 011, and 020).

Changes: To eliminate the need to stop the program to enter the height value (h), change the ¦ instruction to a l 1 instruction (because of the above deletions, R1 is no longer being used) and store h in R1 before running the program. To clean things up, let's also alter O 4 (line 006) to O 2 and l 4 (old line 016) to l 2, since we are no longer using R2 and R3.

The editing process is diagrammed on the next page.

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HP 15c Scientific manual Examples, Deleting Program Lines, Inserting Program Lines