CNIT 340 Loops

what does a while loop do

perfom code while a condition is true

what does a until loop do

perform code until a condition becomes true

what does a for loop do

perform code once for each item in a list

what does a select loop do

list a set of choices from which the user makes a selection

what is a nested loop?

loop placed in the block of code of another loop

any loop type can be nested in itself or any other loop type (t/f)

true

how many layers can you nest loops?

none, there is no limit

what are the three separate commands in a while loop?

while , do , done

the in a while loop can be a command (t/f)

true

in a while loop, the code is repeated until the is true (t/f)

false, it is repeated until the is NOT true

if the is true, a while loop executes commands between 'do' and 'done' (t/f)

true

if the is not true, the code is reevaluated and tries until it is done (t/f)

false, code is skippped to the next command after 'done'

what is the opposite of a while loop?

an until loop

what are the three separate commands in an until loop?

until , do , done

in a until loop, the code will repeat until the equals true (t/f)

true

in an until loop, if the is not true, the code between 'do' and 'done' will be executed (t/f)

true

if the is true in an until loop, skip to the next command after 'done' (t/f)

true

what are the two types of for loops?

standard and three expression

what is a three expression for loop used for?

numeric processing

there is a $ in the variable in a for loop (t/f)

false

what is 'seq'?

external program that creates a sequne of space delimited values

what is the 'seq' equivalent in BSD?

jot

what is the syntax for seq?

seq

what does seq increment by?

if is ommitted...

it defaults to 1

if is ommitted...

it defaults to 1

seq can be used for the for loop (t/f)

true

the select loop is used for what type of user interaction?

user input

how is user input decided in a select loop?

choices are presented in a numbered list

what happens if a valid selection is made?

the variable is set

a code block is ran

the choices are represented again

in a select loop, what happens if a valid selection is NOT made?

the varibale is NOT set and the choices are represented again

is the code block executed if a valid selection if NOT made?

no, code block is NOT executed

how can you break out of a loop?

'break' command

'break' is always required in what type of loop

select

how can you skip to the next value early?

use 'continue'

what does 'continue' do?

stop processing the code block and go to the next value (if it exists)

'continue' can be used for error tapping (t/f)

true