AP Computer Science 3.1 Review of the Basics

shmoop overflowed running All right so let's go let's Start

with a look at what This coat actually does Step

by step we'll first we create a double variable called

numb with the value is your appoint one Then we

begin a four loop that starts with an injured eye

at zero stops when eyes no longer less than one

hundred and increment i by one Each time the loop

is run Essentially this loophole run one hundred times each

son loop cycles we make numb equal the value of

one divided by num minus nine point nine Phillips put

real numbers to it This means for the first generation

one divided by num a zero point one would equals

ten Got it one by one then ten minus nine

point nine his point one And we're back where we

started so Luke will run 99 more times and since

none will always equal point one when we cycle the

result will always be point one again In theory we're

dealing with a double variable here double means double precision

floating point variable got it and floating point variables aren't

the rigid representation of riel numbers we might expect In

fact the floating point bearable is more like a very

good guess at a very precise number It's never quite

exact even the very simple point one plus point two

in floating point variables wouldn't give you a point Three

you get something like point three zero zero for or

thereabouts hearts let's try something if you have your compiler

handy add the following lines to this code and run

it and we'll see what happens if you don't have

your compiler handy well and just we'll put system out

front line number right here in the loop That way

it'll print the current value of numb each time the

loop cycles and we'll be able to see how it

changes over time and for those not ableto participate Well

here's a picture of wild turkey these things you're huge

all right and here's what The result looks like weird

Right What happened Well the imperfections in the floating point

operations kept magnifying themselves over and over and over getting

worse and worse and loris with each iteration before finally

settling in at negative ten Those faras our potential answers

go option a Yep they're being overflowed No no overflow

ares occurred Option b there will be under flow so

after running numb will equal zero Also no option c

after running numb will equals your appointment Well sure the

code may look like things will remain in zero point

one on paper but using a floating point variable means

the exact value of zero point one is not gonna

happen Option d after running none will not equal zero

point one Well that's right For a moment it even

seemed like num was equal to just about everything but

zero point one option e both andy well no ass

for overflow and there was no So our answer is

d and we're number one or rather we're number one 00:03:12.768 --> [endTime] point lobo too