STOP : Stops execution of currently running program including from within any
subroutines and returns to calculator display.
Show program termination message when in interactive text or GUI mode.
syntax: STOP OR
STOP "<string>"
STOP stops execution of a program and returns you to the main calculator
display. The message "<program ended>" will also be displayed when the
calculator is in interactive text or GUI mode. This message can be
customized by supplying the STOP command with an argument string.