EXEC: Executes a pre-written calculator program saved in a file. All calculator program files must have the extension ".prg" The name of the program passed to the EXEC command is simply the file name excluding the extension, so if you want to execute the program in the file "sample.prg" for example, you enter "EXEC sample" into the calculator

syntax: EXEC name

Each command of the calculator program must be preceded by a colon ":" before anything else is entered. Note, unlike calculator input files, line termination with a semi-colon ";" is not necessary for program files.
Valid commands recognized by the calculator includes any normally entered functions, operators, values and variables as well as the following additional program control and program input/output instructions

Program Control Instructions:

IF

conditional execution of a single command.

IF-THEN

Conditional execution of program segment.

IF-THEN-ELSE

Conditional execution of a two-branch program segment.

FOR

Repeated execution at a specified number of iterations of a program segment.

WHILE

Repeated execution of a program segment while a specified condition is true. Testing of condition is done prior to the execution of the program segment.

REPEAT

Repeated execution of a program segment until a specified condition becomes true. Testing of condition is done after the execution of the program segment.

END

Identifies the end of a group of commands.

PAUSE

Suspends execution of the program so you can see answers or program output.

LBL

Label used by goto command.

GOTO

Go to a specified location in the program indicated by a LBL label tag.

IS>

Increment and skip command. See command specific help for more details.

DS<

Decrement and skip command. See command specific help for more details.

MENU

Displays menu with choices shown as multiple branches to different locations within the program.

PRGM

The PRGM command is used to execute other programs from the currently running program as subroutines. Syntax and accepted input is same as the EXEC command.

RETURN

Quits the subroutine and returns to the calling program.

STOP

Stops execution of currently running program including from within any subroutines and returns to calculator display.

Program Input/Output Instructions:

PROMPT

Displays each variable one at a time and prompts user to enter data for each one with a "=?" prompt.

INPUT

Prompts user to input into a variable with a "?" prompt without any preceeding text or displays some preceeding text followed by the "?" prompt.

DISP

Displays one or more strings or variables. Expression arguments are evaluated and the results displayed.

GRAPH

Displays a two dimensional cartesian graph of an expression or the results of a function performed on an expression (not available in text mode).