Loop...endloop loops, Repeating a loop immediately, Lbl and goto loops – Texas Instruments PLUS TI-89 User Manual

Page 316

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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:

At the beginning of the loop

Executed only if the condition is true.

At 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.

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