Buckys C++ Programming Tutorials - 27 - Random Number Generator

[@andrewlozano9473]

I've been watching your C and C++ tutorials for some time now. When I don't fully understand something from my programming books, your videos are the go to videos to complement what I'm currently learning. Thank you!!

[@Scottmilton1favs]

cout

[@Scottmilton1favs]

Yeah, me too. Good video. :-)

[@saltyman7888]

std::cout

[@rohinp784]

Anonim Vere-Casper ;

[@gamingwithus_yt5109]

return 0;

[@shalinisahnimankatalia5305]

@@gamingwithus_yt5109 }

[@thenewboston]

@BrixXSM haha i name most of my files and classes foods. mostly whatever im in the mood for when i make the file

[@MrAnonymousCitizen]

I am know I am a bit late, but this also goes for anyone having the problem. In order to actually get a random number (I don't know why it defaults to 41 if you don't do this.) You must call srand() and give it a time. NULL gives you a random number, otherwise it uses system time. So in your main loop type: srand(time(NULL)); Hope I helped! :D

[@atharvdeshpande5408]

i know this is super random but its been 10 years since you commented, what did you end up doing in life lol, did you continue programming?

[@jasonjjj27]

Thank you so much for your video series, I'm in a c++ online class, so everything I have to learn i have to read from this huge complex book, watching your videos is helping so much. You speak clearly and explain the concepts behind it well. Thank you

[@geml1n]

Bucky, I seriously cannot thank you enough for these videos. Our professor links all of your videos that are relevant to the lecture and I never thought I would really use them...until today. The day of the final. I am wanting to be a mortican, not a coder but I am 80% complete with my degree, so i HAVE to finish it. It is hard to push yourself to complete something you don't even need/want anymore. I could not grasp c++ anymore the way I used to. Your videos actually make sense to me and I may have a shot of passing this class again. Thank you for what you do Bucky. Sorry for all the typos. All the best, A very sleep deprived, failing college junior

[@SeRbianPlayingGames]

if any of you guys want a formula for making random numbers from like 2 to 24 it goes like this(at least what i came up with): x+(rand()%(y-x+1)); x is the starting number, y is the ending number

[@JohnnyRelentless]

It's just (rand()%22)+2. You just add whatever you want you want your lowest number to be, and you subtract that number from the maximum.

[@BruceBmk]

NO seRPg is correct your method wouldn't work for bigger numbers say your Min was 1723 Max 1863 Your random numbers would run from 1723 to 1862

[@gurindersingh614]

2+(rand()%24)

[@bekiteru7015]

you rock, how did u come up with this

[@ethannguyen3840]

Sitting in class for 1 hour and had no idea what the professor is teaching. Just for 9:52 watching a video and I completely understand. What a waste of paying tuitions!

[@4g0ny]

i am in a c++ class where the teacher is of little to no use and this is delivered in exactly the way i need for my brain to digest it. a massive thanks to you, and a subscription as well.

[@ahmadshah751]

other youtuber: "don't forget to like, comment & Subscribe" bucky: "don't forget to add your header file"

[@ThatGuyNamedBender]

i love how no matter how short/long the tutorials are from bucky I always end up spending hours watching them [=

[@BloodOrangeLover93]

Dude you just helped me pass my programming exam, this question is always at the end of the paper

[@MikoPellas]

This video gave me that "ohhhhhhh" moment of understanding lol

[@kenosentity6455]

You've been helping me since I was 13 bro.

[@stucknsolve4875]

10 years old video, but best explanation

[@jackschluchter5707]

This man is a better teacher than any professor ive had

[@andeslam7370]

awesome video, much shorter and sweeter than those taught during lectures.

[@lukaskocman7546]

Even after 10 years, it helped me a lot

[@mohammad_bilal951]

opss man this video is 9 years old OMG and you are the best teacher online i ever had thank you very much SIR :)

[@grossio5564]

very MUSH WTH AND OPSS WHAT KIND OF PERSON ARE YOU

[@parcepabs1991]

I’ve watch like 8 9 videos and in 2 minutes you made a much more simpler code and did exactly what I was looking for

[@godwinmandi8761]

Print (" You Nailed It Dude, I Like The Seeding Part")

[@TonyTxT]

what the hell..!! he isn't teaching python

[@hetaeramancer]

@@TonyTxT haha

[@Foolyfish]

THANK YOU, I really needed to know the srand function :P helped out a lot :D

[@Allyg3000]

In order to see the seconds from 1970 or whatever just type: cout

[@tranqilo6453]

This lead me down a rabbit hole of computer history, thanks

[@jaidev2717]

A million second is just 12 days, Bucky.

[@adamalrefai5838]

pretty damn smart huh! -_-

[@angelhernandezvega6064]

We're living in 2020 while Bucky be living in 1970

[@ddaniel.v]

im livin 12 days past 1970 too!

[@Zovioh]

Bucky, you are officially who I'm learning my programming from now. The book I got is horrible and your channel separates the topics much better, so I can easily find what I need for my program.

[@kpippink]

Thanks for all wonderful videos Bucky. I am struggling to learn C++ for my programming class, but your videos help me a lot :D

[@SeifOrabi]

Really enjoyed this tutorial Bucky. I've always had this problem in a simulation I was working on. But at least we know why now. As always, great tutorial!

[@RedsBoneStuff]

Did you know there is computer hardware that allows you to make truly random number generators? It gives you a random value that you use as a seed. It's based on things that are scientifically random (or at least we do not understand them well enough to predict them). Various quantum phenomena are an option here. Quantum mechanics include so much randomness :P

[@LeoMadrid]

+RedsBoneStuff Are you referring to a Psyleron REG?

[@RedsBoneStuff]

Leo Madrid Not sure what they actually are :P

[@vexion15]

This was SOOOO helpful!!! :D I was getting ready to ask a question, but then you went and answered it before the video was over!

[@TakingItCasual]

I want to scream my love for his tutorials but that'd make me look like some sort of fan boy, finishing his tutorials just fills me with... bliss.

[@Adraria8]

The algorithm for random number generation is pretty simple actually. It basically involves multiplying really large numbers and taking their modulus on another really large number and using that as the next seed. Look up the linear congruential algorithm. You're vids r really helpful by the way!

[@fifaham]

@6:31 you may use the time function then use seconds and mints and probably date, mix them together or multiply them or whatever, so to make it look like more random

[@ben1996123]

if anyone is struggling with rand(), and getting the correct range of numbers, use this: x+(rand()%(y-(x-1))) gives a random number from x to y inclusive, eg: 5+(rand()%(10-(5-1))) generates a number 5, 6, 7, 8, 9 or 10.

[@onelerv1]

This is by far the best explaination of rand() I've ever seen, seriously bucky very very well done man.

[@m4t4m0r0s]

Best video I’ve ever seen about this topic

[@nextblain]

FUN FACT: if u generate random numbers between 1 and 365, about only 30 of em, its almost sure that u will find 2 numbers same! (its called birthday problem from probability) awesome tut bucky! :)

[@meloon2879]

you are the best! Keep doing these videos plzzzzzzzzzzzzzz!!!!!!!! love the way you teach and your humour is the best!

[@kevinramdass8608]

Thank you so much bucky youre a lifesaver...I appreciate your work so much

[@tunamay0168]

Thank you so much for saving a CS major student life

[@ammarshah2366]

Yes, I can confirm that rand() doesn't truly generates random numbers. When I first called out rand(), it printed the same 41 as yours. Btw, thanks Bucky.

[@realmrjangoon]

This guy is so good, I can watch the video at 2x speed, save time and understand the whwole thing

[@hypermeero4782]

THANK YOUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU ur explanation was direct into the point simple LEGENDARY

[@amygonzales8343]

Ugh I finally understand how "seed" works. Bucky kicks ass!

[@helloworld12321]

It's 2021 you r the best❤from Bangladesh

[@tony2351992]

you are randomly amazing. love your videos man keep it UP

[@xbz24]

Bucky u are truly a god love you fella, SIMPLE ENOUGH

[@yousefgamal4557]

Your video was amazing, keep up the good work. I appreciate that, man.

[@arnold9448]

You're amazing in teaching! Love it!

[@loading_wait]

the algorithm does not change every second. it changes at every call of srand(...)

[@Rigardoful]

If I am not mistaken , rand() is actually a recursive function. It uses the result it last generated, to generate the next. So wha t srand() actually does, is make it not take the last result, but the number provided by it, or maybe one generated after a few calculations from the number you gave in srand(). That's what I was told at my university at least, I'm in my first year in ECE department, so I am not the most reliable source :D

[@valizeth4073]

1. Avoid "using namespace std" 2. Avoid "rand", use the contents from instead.

[@kfdjhnhurjnnbjhu3ip410]

no

[@Rawoonah2cool]

thanks dude,short and sweet tutorial

[@Futureblur]

Just as sweet as your profile pic :D

[@hamedalwafi8717]

I hope everyone appreciates these tutorals cause bucky u are fucking awesome ❤️❤️❤️❤️🔥🔥🔥

[@KFilmsProduction]

Random numbers in C++ have an algorithm, like (previous random number *((x*y + z)%n * m - k)/t ...) something like that, so the result is the same for it's first run on a computer, because it's using an algorithm, which uses constants and depends on value generated before. The probability of getting any number is almost equal, so the algorithm is considered as a random number generator. We need to change something, that bucky says :)

[@NeilRoy]

One handy feature of srand() is you can have the user provide a number for something like a level generator for a game (this is how many level generators work, where you can provide a number and it generates the same level, minecraft does this for example). You're just providing your own seed value. This can be handy, just so you know that you don't always want to use time(). Also, random number generators are not all t hat complex. I have written my own, and the reason why I wrote my own was so that if I ported my game to another computer system (different compilers use different algorithms for rand()) I had the same code for generating random numbers on all systems and so I get the same results. You may want to have the same seed so you get the same "random" set of numbers each time for a level generator, OR, you may have a game where you want the enemies to act the same way each time it is run so the player can get used to what happens in what order and they can learn to get past certain levels, so there is a certain amount of predictability. Here is the world's smallest random number generator (there are much more complex generators out that t hat produce much better, more unpredictable results, just google it). This works nicely, try it out... *unsigned long rng_seed;* *unsigned long rng(void) {* * return ((rng_seed = (rng_seed+1)*314159265L) >> 16) & 0xFFFF;* *}* Just set *rng_seed* to whatever seed value you wish (like time() or a fixed value), and then call *rng()*, using it the same way you would *rand()*.

[@farhatmohammadi7224]

I love you Bucky !

[@moharjana]

Sir You are cool and awesome :)

[@samirgunic]

You would need a super accurate clock and a super fast computer to predict the seed before the computer that's generating the supposedly "random" number generates that number. You would also need the source code for the program and the function definition. It's not totally impossible, but it's not something most of us would ever want or need to do anyway. So pseudo-random numbers are good enough for most of us, and for most applications. Only a quantum computer would be able to generate truly random numbers, which is one of the reason they are hyped as the definitive solution for encryption.

[@RealCoDeR]

Very good video . Waiting for Python programming ⌛

[@lorenzorosales2916]

Thanks!!!!!! You explanation is clear and very helpful.

[@asafel]

love your videos!!! thank a alot!

[@Gervisj]

Thanks Bucky. I love the way you explain everything. You're awesome dude!

[@radnyx_games]

Yes but you would probably be using a different random, which is using different number modifications. Random isn't static, so time will only effect the random number you are generating at that time. (I'm not quite sure, but time is either updated every second or millisecond, if it's ms, then we don't have to worry, otherwise... goodluck?)

[@isaacsarte2708]

how about generating random numbers without repetition using array? in c++

[@georgerotariu3221]

Really helpful and well made. Keep it up!

[@OmgitsLiz]

cout

[@dikukhanikar2837]

Wow... your explanation is sooo good

[@Qazqi]

If you don't call srand(), the seed is 1 by default. Therefore, every conforming implementation will give everyone the same sequence until they change the seed.

[@321DiagnoZa]

great tutorial, I am curious to know how can I find the greatest and smallest number after the ocmputer randomly generates the numbers?

[@ilbutti6796]

put results in a vector, than make a function that keeps in argument that vector as const reference, than make that function with a temp value, than, starting with a for loop from vector[0] until vector[vector.size()-1] if vector[i] > tmp { tmp = vector[i] } and make it return after the whole vector has been checked (the same but with < for the smaller. (if you know that your random numbers can't be, e.g. like in this video, > 6 or < 1, you could also optimizd your function by making it return directly when it finds a 1 or a 6)

[@blind_neighbourhoodNerd]

excellent video man Thanks so much

[@GertSmith-w3s]

Please help. Just a quick question. How did the compiler / program know that; I wanted the srand(VALUE), that was influenced by time, to be used in our 1+(rand()%6) equation? We never told it. Did we? :) BEST TUTORIAL ON THE NET. THANKS SOOOO MUCH

[@TheCareertalk]

The numbers aren't really random. They just seem that way because the computer uses a complicated process to generate a number that seems random to humans. You need to "seed" the random number first. Bucky talks about this in the video.

[@muhammadhariskhan8204]

Best Programming Teacher

[@sydneyricafort4761]

i really love your videos bucky thanks a lot

[@HappyDancerInPink]

Could you put the rand function into the srand parameter to get an even more complex random number generator?

[@jaredcubilla7770]

cout

[@SuperYtc1]

Nope because srand(rand()); would be the same as srand(41); The seed would be the time every time, so the random number list would be the same.

[@hassansardar6649]

Love you sir Briliant explaination Cleared me well Thank you soo much ..

[@RyansRecording]

you explained it very well

[@johnsoto7112]

why is the program only printing 21 numbers when you made the for loop 1

[@lydiasteinberg5291]

I'm at 6:50 in the video and having trouble with my code. I've done it exactly as he has (except for the srand, since if I can't get this much to work, I don't want to keep going until I can), but it keeps giving me these two error messages: "error: expected primary-expression before '(' token", and "error: expected primary-expression before '

[@lydiasteinberg5291]

***** Thank you so much! I didn't notice that's what I was doing there, it's really hard to see in the codeblocks font. I can't believe I got stumped on that. Thanks again for the help!

[@togmeister8604]

Bucky, wouldn't that be procedural then if your using a seed? Because when you do rand() it prints same number but when you do a seed it prints same number every time you use that seed. So shouldn't this tutorial be called Random and Procedural Number Generators. When you use the seed it's a predefined value hence it's procedural.

[@qzer1990]

Most enlightening tutorial in a while, thanks man. But what functions do i.e. slot machines use? Probably not a simple rand() I guess. (;

[@danielodette6013]

Fun fact. When I tried rand() the first time, my random number was also 41.

[@valizeth4073]

Because rand is a garbage function and should definitely not be used.

[@SuperYtc1]

@@valizeth4073 What do you think should?

[@vend57]

random numbers are actually generated from the garbage values that are collected when a random variable is declared but not initialized. for instance, if you want to design a rand() function yourself, just follow this code : int main() { int a[100],i=0; while(i

[@marcjooreja5903]

WEheheyW!! thanx a lot man youre realy great!! I love u!!! hahaha!!! this is just what i needed!!!

[@nathliea]

I was trying to use this to generate a number between 1 and 100, so I put in %100 instead of %6, but every "random" result was divisible by 5. I am REALLY new to coding so I am sure I am doing something really wrong, but I did enjoy this tutorial even though I didn't understand most of it :)

[@Darku.Matteru]

very useful tutorial;) thx I needed that random generator rly bad..

[@TheXRealXBrapp]

And I used the loops variable to make it generate a new number EVERY time you use the function, rather than every second.

[@tonyfalapatt1308]

very nicely explained I don't what I can do for you but I liked and subbed and if I can I will watch more videos and like it 😀😁

[@testingnames1995]

How can we print the permutations of the elements in an array? for example the permutations of the numbers 1-2-3 are the following: 1-2-3, 1-3-2, 2-1-3, 2-3-1, 3-1-2, 3-2-1. How would we make a program that can find and PRINT the permutations of the values that the user has added to an array? I have been trying to do that for the last couple days but i haven't been able to succeed... At this point i was only able to print random values of the elements of an array acording to the size of it. I hope you can understand what i'm trying to say and what my problem is. Any help would be appreciated! Happy coding :)

[@peri.platypus]

Now I know, thanks for enlightening me

[@farzambakht8354]

Good Teacher i really understannd very much

[@SeekerofYab]

Thanks for the awesome videos. Also, would it be possible to make a completely random number generator by reading a analog to digital converter at a digit past its accuracy limit? Basically reading the noise?

[@TheCareertalk]

The number that comes out of rand() is only pseudorandom, not truly random. It basically follows a little algorithm to create numbers. It looks random, but it's not quite.

[@hdkimo]

i NEED help i want to generate a random array of 6 numbers ex: 6-5-31-42-27-10-15 and it has to be between 1 and 49 and i want to keep the same numbers while using the console. i dont want it to generate a new number every time i go back and forth in the menus that i created in the console but i want it to change every time i open a new console. thx

[@six2gaming894]

i under stand this but how to i get access to this number like setting it to an int or something

[@pby1000]

How is the value of srand(time(0)) being related to rand()? I hope this is clear. He does not use srand in the cout statement...

[@TheK00paKingdom]

//Since everyone is posting their programs: #include #include #include using namespace std; int main() { cout

[@ibiixie]

+TheKoopaKingdom I might as well do it too.... #include GLfloat light_diffuse[] = {1.0, 0.0, 0.0, 1.0}; /* Red diffuse light. */ GLfloat light_position[] = {1.0, 1.0, 1.0, 0.0}; /* Infinite light location. */ GLfloat n[6][3] = { /* Normals for the 6 faces of a cube. */ {-1.0, 0.0, 0.0}, {0.0, 1.0, 0.0}, {1.0, 0.0, 0.0}, {0.0, -1.0, 0.0}, {0.0, 0.0, 1.0}, {0.0, 0.0, -1.0} }; GLint faces[6][4] = { /* Vertex indices for the 6 faces of a cube. */ {0, 1, 2, 3}, {3, 2, 6, 7}, {7, 6, 5, 4}, {4, 5, 1, 0}, {5, 6, 2, 1}, {7, 4, 0, 3} }; GLfloat v[8][3]; /* Will be filled in with X,Y,Z vertexes. */ void drawBox(void) { int i; for (i = 0; i < 6; i++) { glBegin(GL_QUADS); glNormal3fv(&n[i][0]); glVertex3fv(&v[faces[i][0]][0]); glVertex3fv(&v[faces[i][1]][0]); glVertex3fv(&v[faces[i][2]][0]); glVertex3fv(&v[faces[i][3]][0]); glEnd(); } } void display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); drawBox(); glutSwapBuffers(); } void init(void) { /* Setup cube vertex data. */ v[0][0] = v[1][0] = v[2][0] = v[3][0] = -1; v[4][0] = v[5][0] = v[6][0] = v[7][0] = 1; v[0][1] = v[1][1] = v[4][1] = v[5][1] = -1; v[2][1] = v[3][1] = v[6][1] = v[7][1] = 1; v[0][2] = v[3][2] = v[4][2] = v[7][2] = 1; v[1][2] = v[2][2] = v[5][2] = v[6][2] = -1; /* Enable a single OpenGL light. */ glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse); glLightfv(GL_LIGHT0, GL_POSITION, light_position); glEnable(GL_LIGHT0); glEnable(GL_LIGHTING); /* Use depth buffering for hidden surface elimination. */ glEnable(GL_DEPTH_TEST); /* Setup the view of the cube. */ glMatrixMode(GL_PROJECTION); gluPerspective( /* field of view in degree */ 40.0, /* aspect ratio */ 1.0, /* Z near */ 1.0, /* Z far */ 10.0); glMatrixMode(GL_MODELVIEW); gluLookAt(0.0, 0.0, 5.0, /* eye is at (0,0,5) */ 0.0, 0.0, 0.0, /* center is at (0,0,0) */ 0.0, 1.0, 0.); /* up is in positive Y direction */ /* Adjust cube position to be asthetic angle. */ glTranslatef(0.0, 0.0, -1.0); glRotatef(60, 1.0, 0.0, 0.0); glRotatef(-20, 0.0, 0.0, 1.0); } int main(int argc, char **argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); glutCreateWindow("red 3D lighted cube"); glutDisplayFunc(display); init(); glutMainLoop(); return 0; /* ANSI C requires main to return int. */ }

[@TheK00paKingdom]

It waits for the person to press any button.

[@jammes327]

+Josh Griffith Remove the question mark below after the closing curly brace. :)

[@nitishprajapati8546]

+TheKoopaKingdom I think that ** cin.get(); ** is somewhat like ** system("pause"); ** which unfortunately now dosen't work in ANSI C++ compilers....[even clrscr(); dosen't ] However, cin.get(); too didn't work at one command. I needed to write it TWICE for it to work ONCE........ . . However, whats the algorithm or idea behind cin.get(); ....i know that cin is object of standard namespace......but get() ? How this command works.

[@SansP3ur]

Here's an alternative random seed generator that recasts the range from 0 to 4,294,967,295, rather than − 2,147,483,648 to 2,147,483,647: srand (static_cast (time(0)));

[@SuperSebatube]

Hi, Bucky, congrats for this works. I hava a questions about the number 5, what is the case?. Greetings.

[@saraesmayili]

why everytime i use sand(number); before my for loop i got same numbers repeatedly in my result ?

[@inx1819]

Seed the RNG with time(0) like this srand(time(0))

[@angelhernandezvega6064]

you should have watched the whole video