6.1: While Loop - Processing Tutorial

[@kevnar]

A programmer's wife texted her husband. "While you're out, get milk." ...and she never saw him again.

[@potato4687]

well played

[@KamariaIsHere]

🤣🤣

[@mariuspet89]

Hahaha :))) :))) nice

[@GameSteals]

@@jordanclava931 By that example, husband will always be out, and there will never be milk. Hahahahaha

[@itssupremesharma4104]

@@GameSteals maybe thats the point Hahaha

[@martinds93]

If my college teacher putted just "1 bit" of this excitement to the programming classes, I would be happy. But I'm not, and im watching you. Thank you. Your videos are awesome. Im from argentina.

[@kevinch3]

hey tinchou I feel the same. abrazou

[@rawanelabied6654]

HAHAHAHAHAH

[@angelcaru]

*p u t t e d*

[@beatrizlisboasanchez8989]

@@angelcaru He said he is from Argentina, which means English is not his native language 🙄

[@angelcaru]

@@beatrizlisboasanchez8989 Mine isn't either.

[@robertomerani]

Hello everybody. This is my first line of code where a ball bounces from right to left and moves down after reaching the right and left side of the screen. Thank you Daniel Shiffman for your time and patience. I never get tired of watching your videos. float x = 0; float xspeed = 10; float y = 320; float yspeed = 10; float up = 25; void setup () { background (127); size (1280, 640); } void draw () { noStroke (); fill (0); ellipse (x, y, 25, 25); x = x + xspeed; if (x > width || x < 0) { y = y + up; xspeed = xspeed *-1; } while (x < 0) { if (x > width) { y = y + up; } else { x = 0; noStroke (); fill (0); ellipse (x, y, 25, 25); } } }

[@TheCodingTrain]

Nice work!!

[@gg-lu3lt]

If someone still confused about 5:37 (why you have to reset x = 10 inside DRAW) and come across this comment I hope the code below can help explaining a bit more (copy and run it in your program.) There beginning of DRAW. until it reach > 400, then it draw the result) won't wrong, but this helped me understand this better. I also hope this could help you guys as well. Happy coding guys :D float x = 0; void setup() { size(400, 300); } void draw() { background(random(255)); while (x < width) { x = x + 1; fill(101); stroke(255); ellipse(x, 150, 16, 16); println("still in WHILE LOOP"); println(x); delay(10); } x = x + 1; println("outside now"); println(x); delay(1000); }

[@openopinion4208]

i have learned alot from your lectures and still learning.your videos are definitely the best on KZbin and of course amusing.thank you sir for these lectures.

[@haleemulhassan9158]

@5:37 I really didnt get the part where while loop does NOT draw how we expected, as you mentioned. The first time we go into the while loop, x = 0. Now in the while loop is the command of printing circles using the value of x. So shouldnt it keep drawing circles till the value of x>width within the while loop? Why did you have to put the value of x=0 again before the while loop to see any kind of result. Basically what Im asking is how is the value of x = width on the very second time in the while loop?

[@TheCodingTrain]

+Haleem ul Hassan global variables maintain their value each time through draw. Each loop takes x from 0 to width. So when the loop ends, x equals width. When draw starts over again, x still equals width! So in order for us to see the things drawn again, we have to start x back at zero. It's a very confusing thing b/c the while loop is a loop and also draw() is a loop! This video explains a bit more: kzbin.info/www/bejne/kGnWXmqYmrODZ8U

[@haleemulhassan9158]

+Daniel Shiffman Ahhh now I got it. The video sure did explain the concept. Thank you :)

[@abdulrahmankh1611]

Thats the 2ed Time i understand nothing from my trash Teacher and watch your Videos before my exam instead and it really helps, i am thankful

[@popcycleism]

Where is your school at? Coding with visual breakdown. I understand the concept better! Thank you for this!

[@wallaceterra5993]

I really enjoyed your class! His teaching is fun and very lively! Yes, your video came out perfectly, mistakes happen. Thanks!

[@jamesfilosa6277]

5:42 - Wouldn't it make more sense to move "background(0);" to setup instead? ...when demonstrating the purpose of the while loop.

[@blackchan4249]

please continue to ramble on. those bit make the video more interesting. Thank you!!

[@abhishekkattimani1302]

My all doubts with loops are get cleared thank you so much sir

[@owpeezygaming967]

way longer than I expected, hehe i rather watch you even for an hour per episode

[@reibangchakma]

1:26 how did you program that sound?

[@stephmacindoe6075]

Love the Dora reference, went to see the new film for my 20th birthday

[@azrael9986]

if you watch this at 1.75x or 2x speed it's beautiful, it's lovely, this is an example.

[@kushbhogate6263]

better watch at 0.25 x speed

[@Maha_s1999]

You are so likeable as a teacher!!! I love your style! Just starting CS50 and although not quite there with the coding language part (I assume this is C?) I feel this will be useful later 🙂

[@achievementcell4631]

I love this man.

[@chaiyakheourn9970]

I love your teaching so much!

[@ruchisheth9430]

At 5:04, when we are putting ellipse inside the while loop, the first time draw is executed, while function is executed with x being 0, it reaches width n stops but why ain't those circles seen? The second time draw has x =width so while will not execute but first time while function inside draw executes perfectly so why can't we see circles?

[@ruchisheth9430]

Just realized background is the culprit

[@hoaang4759]

Ok

[@brystet6642]

I will never stop

[@raphaelmorgan2307]

"I guess at this point just email if you have a question" the KZbin comments: am I a joke to you?

[@ramachhetri5368]

Him: Maybe you will, also conquer the universe or something. Thanos: I would have done that if the avengers didn't stop me!

[@DruishQueen]

Hi! Why do you use "eclipse" instead of "circle" for the circle shape? Sorry if you went over this and I missed it!

[@fredericomendonca4572]

It's ellipsenot eclipse! And an ellipse might not be a circle

[@DruishQueen]

Frederico Mendonça oh yeah I meant ellipse haha.

[@jacobwojcik9888]

I am having an issue with the starting bit of the video with the if statement. If we only run the block of code when x is less than 16 (the width of the ellipse), then wouldn't we get to the point where x = 16? And when evaluated against width (also with the value of 16) we get a false evaluation where we do not run the block of code, and then simply run the ellipse command with x = 16 over and over again. So, from this perspective the eventual coordinate for the ellipse would be (x = 16, y = 150). My expectations were to see the ellipse at that coordinate over and over because 16 (x) is never less than 16 (width), and so you would never update the value because you never run that line of code due to the evaluation being false. Of course, this perspective is wrong, because we clearly get an output that eventually ends with the ellipse coordinate of (x = 400, y = 150). Sorry for the long winded question, but I just can't seem to reason it through on my own. Any clarity would be greatly appreciated. Happy coding!

[@celiacasimiro465]

9:15 Oh My! I have watched Dora The Explorer, before.

[@parastoon3706]

I had a really hard time digesting the "while" loop and still don't quite understand one thing. Why does it matter to reset x=0? I mean if you put "x=0;" before the While loop, shouldn't it be useless? pulling my hair out here...

[@TheCodingTrain]

Would you mind asking at discourse.processing.org/! It's a better platform for Processing and p5.js related code questions. You can share code there easily! Feel free to link from here to your post.

[@mikejones-vd3fg]

take the background out of the draw function and you'll see it draws all the circles without having to reset it to x = 0;

[@elliotsefaradi4568]

can you do that particle system with the while loop?

[@xuefangzheng6454]

Hi, I don't understand what makes it different when u add x = 0; before the while loop at the beginning of this video. It has already declared x and given it a value on the top of the code.

[@TheCodingTrain]

Would you mind asking at discourse.processing.org/! It's a better platform for Processing and p5.js related code questions. You can share code there easily! Feel free to link from here to your post.

[@andreacoricciati4909]

What if I wanna make it go to left once I reach mouseX > 300?? I tried with x = x -1 with an if statement that says if(mouseX > 300 && mouseX < width){x = x-1} but it creates another loop once I reach 300 , it doesn't go "turn" the loop fo the left.

[@MiksCasal]

Conquer the Universe. Yes. :D

[@cyberguide_in]

Hi Daniel, I did not understand why did you declare x = 0 again if you had already done that earlier in the beginning float x = 0; ?

[@TheCodingTrain]

+BABLU KUMAR Since draw() is repeating over and over again I need x to be reset back to 0 each time. The global "float x = 0;" could actually be removed here and only declare x in draw().

[@cyberguide_in]

Thanks a lot. Well, I sent you a mail as well a few days back. Maybe you forgot to reply.

[@theaeleonore4359]

okay yeah I understand that, but how do I get rid of the previously drawn ellipse with the while loop?

[@aangel-s2p]

nest background in the loop so it draws new background every loop

[@rishoo6976]

instead of doing x = x + 1, couldn't you do x++ or x+= 1?

[@TheCodingTrain]

indeed!

[@jusaggoldcow1125]

u R getting good at the back and forth thing dan! lol

[@mlittleprogramming780]

Great video!

[@valbrownsmith5656]

Since draw is already a loop, can't you use that loop instead of a while loop?

[@debanjanaghosh6634]

Writing int x=0 as global does nothing. local int x=0 in draw() makes the program run. Why? Please help

[@ryanharris4066]

Why mouseX actualizes with the "if"?

[@TheRealHedgehogSonic]

Whenever I try to make a while loop in the draw() method of my programs, the window crashes. Can anyone tell me why?

[@SuperMan-pd3kg]

thank you mate you were a great help

[@tehnay4817]

Instead of adding "fo"r statement inside "while", i just put "x=x+mouseX+1;" and got the same solution, i dont know should i, but i am just a little proud of myself for, making code smaller, by myself.

[@Elxuekos]

take your time and dont worry, hopefully we'll get better explanations

[@georgikocharyan3305]

Hey, can I ask a question? If I change mouseX to mouseX / 5 as to create less of a space between circles, it works as intended, until mouseX drops under 3 (checked with println). Why? I can't really find out, I've tried a lot of things but it crashes as soon as your mouse dips left.

[@georgikocharyan3305]

nvm, solved it! Processing lops off the comma, so as soon as mouseX / 5 reaches 0. something, you get 0!

[@post_hit_invincibility9940]

Noob Question. When x is definded as 0 over and over again, this should mean that x = x+10 always definses x as 10, or? I do not get the logic here. Any Help? :)

[@puphuc9415]

x is definded as 0 over and over again, because he use background on draw(), so when the first time draw() finish, the result will be like we expect but because background on draw() and the x still = width so while() not work and screen still balck . So he must put x = 0 to each time draw{} execute to while() do its job. I am not native english speaker so i have some problem with this help. forgive me if you don't understand my answer because my poor in english

[@gauravbanwari1981]

if the background is in void draw(),then why dont we see the ellipse moving ? Instead there are multiple copies.

[@ivanlin7995]

because the while loop is place after the background(), when draw() begin, it sets the background first and draw all the ellipse then run draw() function again. draw -> set background -> draw ellipse -> draw -> ......

[@jaredlester5628]

What is the value of width?

[@f_u_n_e_r_a_l]

Dan I miss to see all this great content, get well soon :)

[@s.peanutbuterson6733]

what happened?

[@oorschot5626]

I don't really get what happens when you reset X back to 0 every time through draw.. ?

[@RobberDoDoro]

How to make the code of the bubble falling down? (the begin of this video one) thank you~

[@timeslongpast]

Copy this into your code :D if(circleY > height || circleY

[@SpyrodoZ]

can someone tell me whats wrong whit this code? void setup(){ size(500,500); } void draw(){ background(255,0,0); x = 0; { while( x < width) x = x +1; ellipse(x,250,50,50); } }

[@rohanj96]

you didn't write float x; in the top of the code. so the pc couldn't understand what x was. That's what I think the problem is

[@---xp7yw]

it is because you didn't initialized the x.

[@usmanlatif4985]

hmmm.. copied and pasted this yet I get the following error "Script error. (: line 0)"

[@Quidoute]

int thanks = 0; while(thanks < infinite) { println("THANKS and i hope i did no mistake"); }

[@宋文鹏-v6f]

hey i have a question Why the video does not end？

[@hectorgarlinga2899]

the draw function contains a for loop?

[@hectorgarlinga2899]

+Daniel Shiffman thank you for your explanation, just saw the video "6-4A Loop Inside Draw" where you explain just that . i am amazed all the things you can do with processing, seems a very powerful tool.

[@Calz20Videos]

I added a y... kinda could work as a coordinate plane.

[@Majestic12zombies]

i dont get this code to work, when i move background to setup it works but yours is in draw and it keeps working, im in python's module and my code is the one below: x = 20 def setup(): size(600, 600) #background(0) def draw(): background(0) global x while x < width: fill(255) noStroke() ellipse(x, 20, 20, 20) x = x + 20 if someone knows it would be very useful, thanks :(:

[@Majestic12zombies]

nevermind, for some reason the variable x should have been below draw function not above setup, i dont know why but it worked :)

[@nenasaniatadaoaten5818]

what if num1 = 3; num2 = 2; (num1 > num2) is this true ?

[@johnnycincocero]

How can I turn these sketches into .gifs?

[@TheCodingTrain]

+Johnny CincoCero I would take a look at saveFrame() which allows you save a sequence of images that you could stitch together into a GIF. processing.org/reference/saveFrame_.html

[@johnnycincocero]

Thanks, Sir.

[@Hydr312]

what is with the "do" loop ? how this work

[@Smellycheecksyt]

I’m moving too fast 💨 😂

[@angelcaru]

The difference is that the code in do...while(...) loops always executes at least once. For instance, while(false) {...} would never run, but do {...}while(false) would.

[@7cmhg840]

Why is the subtitle in Portugese? Are you Portugese?

[@made2youtv336]

want more video bout this plzzz

[@kevinch3]

Thank you smiley guy. When I can I will subscribe you

[@artistalreem1180]

Write a C++ programme that reads a sequence of integers terminated by zero value then finds the percentage of the negative numbers and the percentage of the positive number in the sequence. The programme output is as shown: : Enter a sequence of in integers terminated by zero 6 -7 -8 10 -12 14 15 2 -6 the percentage of negative numbers is 44.4 the percentage of positive numbers is 55.6

[@dr__ey]

OMG I SCREAMED OUT LOUD WHEN I GOT 0 for mouseX omg

[@farazk9729]

Conquer the universe! Hahahaha!

[@luisnannini]

deadmau5 - while(1

[@caleblonggrear2796]

/‘sjjkkkkkkkkmna kno n in

[@angelcaru]

while(true);

[@sidhuz633]

just ad x = x + mouseX + 1; there you go

[@sidhuz633]

but add if condition is best because we need x = x + 1 for once only when mouseX

[@rabeaahsan2070]

cool

[@ZoyaKhan-we8zi]

i need c compiler

[@techgaming1125]

Uh-huh!

[@RealDTSM]

anyone here watching as a programming student? like if you are(not leeching likes i promise)

[@hoaang4759]

Ok

[@altaccount8392]

Bruh said ok

[@mccallumc]

Zero!

[@khuzairimohamad]

whos from mmu? raise ur hand