Texas Instruments TI-89, TI-92

Chapter 17: Programming 299

17PROGRM.DOC TI-89/TI-92 Plus: Programming (English) Susan Gullord Revised: 02/23/01 1:14 PM Printed: 02/23/01 2:18 PM Page 299 of 40

A Loop...EndLoop creates an infinite loop, which is repeated

endlessly. The Loop command does not have any arguments.

:Loop

: --------

:EndLoop

:--------

Typically, the loop contains commands that let the program exit

from the loop. Commonly used commands are: If, Exit, Goto, and

Lbl (label). For example:

:0!x

:Loop

: Disp x

: x+1!x

: If x>5

: Exit

:EndLoop

:Disp x

In this example, the If command can be anywhere in the loop.

When the If command is: The loop is:

t the beginning of the loop Executed only if the condition is true.

t the end of the loop Executed at least once and repeated

only if the condition is true.

The If command could also use a Goto command to transfer program

control to a specified Lbl (label) command.

The Cycle command immediately transfers program control to the

next iteration of a loop (before the current iteration is complete).

This command works with For...EndFor, While...EndWhile, and

Loop...EndLoop.

Although the Lbl (label) and Goto commands are not strictly loop

commands, they can be used to create an infinite loop. For example:

:Lbl START

: --------

:Goto START

:--------

As with Loop...EndLoop, the loop should contain commands that let

the program exit from the loop.

Loop...EndLoop

Loops

Note: The

Exit

command

exits from the current loop.

Repeating a Loop

Immediately

Lbl and Goto

Loops

An If command checks

the condition.

Exits the loop and jumps to

here when x increments to 6.