HP 48gII Graphing, 50g Graphing manual Using Subroutines, To recall the current flag states

To recall the current flag states:

Execute RCLF (!°L %MODES% %FLAG% L%RCLF% ).

RCLF returns a list containing four 64bit binary i ntegers representing the current states of the lower and upper groups of system and user flags:

{#nsystemlower #nuserlower #nsystemupper #nuserupper }

To change the current flag states:

1.Enter the flagstate argument — see below

2.Execute STOF (!°L %MODES% %FLAG% L%STOF% ).

STOF sets the current states of flags based on the flagstate argument:

#ns	Changes the states of only the system flags.
{ #nslower #nulower #nsupper #nuupper }	Changes the states of the system and user flags.

Example: The program PRESERVE on page 26 uses RCLF and STOF.

Using Subroutines

Because a program is itself an object, it can be used in another program as a subroutine. When program B is used by program A, program A calls program B, and program B is a subroutine in program A.

Example: The program TORSA calculates the surface area of a torus of inner radius a and outer radius b. TORSA is used as a subroutine in a second program TORSV, which calculates the volume of a torus.

The surface area and volume are calculated by

A = π	2	( b	2	– a	2	)	V =	1	π	2	(b	2	– a	2	)( b – a)
								--
								4

(The quantity π2(b2 – a2) in the second equation is the surface area of a torus calculated by TORSA.) Here are the stack diagram and program listing for TORSA.

Level 2	Level 1	→	Level 1
a	b	→	surface area

RPL Programming 129