HP 15c - Manual (Page 82)

82
Section 7
Program Editing
There are many reasons to modify a program after you've already stored it:
you might want to add or delete an instruction (like O, ©, or
¦), or you might even find some errors! The HP-15C is equipped with
several editing features to make this process as easy as possible.
The Mechanics
Making a program modification of any kind involves two steps: moving to
the proper line (the location of the needed change) and making the
deletion(s) and/or insertion(s).
Moving to a Line in Program Memory
The Go To (t) Instruction. The sequence t “ nnn will move
program memory to line number nnn, whether pressed in Run mode or
Program mode (PRGM displayed). This is not a programmable sequence; it
is for manually finding a specific position in program memory. The line
number must be a three-digit number satisfying 000 ≤ nnn ≤ 448.
The Single Step (Â) Instruction. To move only one line at a time
forward through program memory, press  (single step). This function
is not programmable.
In Program mode: Â will move the memory position forward one line
and display that instruction. The instruction is not executed. If you hold the
key down, the calculator will continuously scroll through the lines in
program memory.
In Run mode: Â will display the current program line while the key is
held down. When the key is released, the current instruction is executed, the
result displayed, and the calculator steps forward to the next program line to
be executed.