Java Programming Tutorial - 26 - Random Number Generator

[glampkoo]

you should take the "ln".

[ottozeimer]

Bucky, thanks for a great tutorial, I am currently on the 26th tutorial video atm, but I have already programmed sort of a beta of Dice Poker. It works :)

I am 100% tuned in!

[dragonthewatcher]

why the fuck is eclipse suddenly shooting up from 2% cpu usage to 75% cpu usage when i try and do simple stuff like create and delete clases with nothing in them... and it takes like 10 minuts.... dafuq

[Roger4313]

Type: sout then press tab its much faster

[kidharris55]

Hey Everyone! im a 15 year old teaching myself java from bucky. i watched most and understood most of c++ but im sticking with java. java is easy and fun. i have mad a legit guessing game using the random number generator. i did this all by heart of all the knoledge i know so far from programming. i am releasing the code. Message me for link! to see it Maybe this can help anyone in a way?! im on youtube 24/7!

[gustavboll1]

it can't return 0

[B1KMusic]

@VictinaJustev you forgot ===, which tests if the types are the same, for example, 25 === "25" returns false because "25" is a string and 25 is a number. string != number. However, == tests equality on terms of value. "25" == 25 returns true because 25 = 25. using simply = is for assigning something. This is stuff a programmer should just know.

[B1KMusic]

With the for loop can't you just type "for(i=0;i<10;i++)"? it's a lot easier.

[COD5252]

why he uses "number +" everytime for the last few tutorials for output

[MisterMadPanda]

@COD5252 he does 1+ because if you don't the number of the generator will begin at zero and end at the number before what you wrote. if you put +1 you get from 1 to your number.

[somedude491]

Now You Know how To win At Runescape dice Games (:

[BGFreerunner]

how can i use an if statement with this. For example in a magic 8ball program. I want to generate a random int then do If int=1 sysout("yes") ect with other numbers. It says cannot convert int to boolean. Help please.

[wingnutlord]

My numbers didn't match yours? Jk

[NICKcoolize]

i use syso (control space)

[jrjy3]

Couldn't you use the Math.random method and then you get something like 0.293847384753847573? Then all you would do is multiply that by 6 and add 1. Then you could use the rounding methods.

[KristopherSw]

Anyone else going to make a slot machine now?

[BlackZeroHawk]

how can i ask the user if he would like to play again? y/n nd when he says yes the program runs again help pls. like whats the code for it?

[t4techy]

Most of the time, views decrease as the video number goes up but I guess as this video teachers you how to build an ACTUAL program the views have gotten higher. Thanks bucky for your java help, they're real easy to understand :DD

[jspspike2]

all I get is  java.util.Random@586dd8f1

[C0GSniper]

In the last System.out.println(), what do the empty quotation marks do? It works fine without them.

[MrBuskaroo]

I'm trying to do this, but the numbers have to be unique.. Can't figure it out >=|

[C0GSniper]

@MrBuskaroo What do you mean?

[MrBuskaroo]

@C0GSniper I mean the values that are returned cannot be duplicates, they all have to be unique, I figured it out anyway.

[ybman]

@MrBuskaroo Out of interest, what did you do?

[MrBuskaroo]

@ybman Have you got an e-mail address and I can send you the script? It would be so much easier to show than explain.

[korkypnoy]

can't you just make the random parameter number to 7 instead of 6 if you want an extra number for random generation?

[theSketchyCoder]

@korkypnoy

Well, yes and no. You would certainly get an extra number, but there'd still be the possibility to roll a "0". The point of adding 1 was to alter the range from "0-5" to "1-6".

[korkypnoy]

@theSketchyCoder oh ok, yeah I get it now thanks a lot :)

[Alavistaven2012]

I'm understanding how fighting games work now.

[TalonsFriend]

like 1101010001010101001001?

[TalonsFriend]

*values



[TalonsFriend]

Is it possible to get valus between 0 and 1?

[menthus123]

@TalonsFriend double number = dice.nextint(1);

[HectorFaelisy]

goddamit I get 2's and 5's all the time to!

[MultiGamerDA]

Why doesnt he show the tuna.java class ?? Bdw nice vids :D

[MyBlindRun]

HELP

I managed to get different numbers to you?

What did I do wrong lol jokes

[jas16899]

You don't even write an algorithm?

[SpidarStar]

I wanted 5 numbers... I got 3 1 4 1 5.... PI!

[NebulaOrbit]

i got a question. at school we also learned that you can just use:

double dice=Math.random();

then you cont have to import the java.util.Random

is there any difference in this one and the one you used?

[Mlackey94]

@NebulaOrbit Essentially no if you loop it so it gives dice a new value each time.

[Armaos69]

I got 4 8 15 16 23 42 :/ im kinda LOST!

[zVenFTW]

@Armaos69 You didn't put 6 in the dice.nextInt.

[Armaos69]

@zVenFTW You actually didnt get my comment.. these are the code numbers from Lost series :)

[zVenFTW]

@Armaos69 Actually, you asked something and i answered to it. That's all.

[Armaos69]

@zVenFTW i didnt blame you bro.. you did the right thing :) Thnx for your reply :)

[HTMLMINECRAFTGUYJAVA]

@Armaos69 You might have added an extra number in there,

[TheExplodingPumpkin]

@Armaos69 Unless you put up the maximum, that wouldn't be possible.

[chucky207]

@Armaos69 Ok .... (another example of wt he said) :

if we want to find random numbers between 51 and 70 we need to say :

num=51+ obj . nextInt (19) ;

51 -> from where it's starts

19 -> how many number after 51 ( 51+19=70)

[PeacedDollar]

How would I make it pick a random string from an array? I have my static variable with an array, but I can't figure out how to make it pick a random thing from the array...

[Armaos69]

@PeacedDollar i think you should make a random variable to use it as an index for your string array e.g.

Random rand = new Random();

int index = rand.nextInt(Here you put the array's length);

And then you go do whatever you like.. something like:

String randomselection;

randomselection = nameofyourarray[index];

Hope that helps..

[PeacedDollar]

@Armaos69 Thanks a lot!

I will see if that works.

[shipmaster4000]

:P I didn't figure out how to make other things so i made it say # Well your lucky number!



[Everlovingful]

wow I could make a program that counts the number of swings required to kill a beast with 100K health and I embedded a simple crit chance there=))

[zVenFTW]

@Everlovingful Depending on the max amount of damage you can do public static void main (String[] args) { Random rand = new Random(); int swings; int randomcounter = rand.nextInt(10000); int dmgdealed = 0; for(swings=1; dmgdealed <=100000; swings++) { dmgdealed += randomcounter; System.out.println(swings); }

That will deal between 0 and 10.000 damage. For the critical chance, etc. is harder, but you will have no problems doing it using this concept.

[kamul8]

if you want to type in "System.out.println();" you can just type "sysout" and press ctl+space. works great and is a lot faster!

[richieallen1000]

@kamul8 it is alot faster thanks man!

[GeekyMe97]

@kamul8 Thanks! How did you find that out? ^^

[kamul8]

@GeekyMe97

by watching a lecture on "Java in Eclipse"

/watch?v=dYwVAi3TPrk

sadly its in german, so if you dont speak it, dont bother watching ;-)

[GeekyMe97]

@kamul8 Crap >-<

I'm learning German, but far from being able to listen to people talk it .__.'

[kamul8]

@GeekyMe97

i just discovered that pressing [clr]+[shift]+[L] gives you a list of shortcuts.

have fun!

[tonilocoable]

@kamul8

or just "Syso" and ctrl+space, but shortcuts aren't good for beginners.

[Decodeish1]

@kamul8 thanks :)

[Decodeish1]

@kamul8 you can also write syso and then ctrl + space ;D

[kamul8]

i know, but "sys(tem.)out" makes more sense and is easier to memorize

but i use"syso" too ;-)

[Mtc529]

@kamul8 You can just write "Syso" and then press ctrl+space, actually :)

[TheExplodingPumpkin]

@kamul8 It's amazing. Thank you a lot! :D

[ToTCaMbIu]

@kamul8 where did you get your shortcuts from?

[barryt06]

@kamul8 works with syso also

[Patrick128000]

@kamul8 Even faster is syso + CTRL + SPACE

[kamul8]

@Patrick128000

i know, i just wanted to tell people the longer version because it is easier to memorize

but i use syso too...

[imkoreandontmess]

i have always wondered why you leave space between " "

Ex,

System.out.println(Hello + " ");

[mjdhiru]

@imkoreandontmess he laeves a space so that the words look nicer .... for example System.out.println(Hello + " " + Bucky) will print out as "Hello Bucky" Wheras if u do like this..System.out.println(Hello­ + Bucky).. i will print out as "HelloBucky".. this is why he uses a space between them...

[Minecrafter797]

In the end he almost said "play along with it" but he corrected himself.

[cowbox101]

999999999 is the number i used

ooooppps!!!

[miguelaerosmith29]

so usefull

[awsmB34r]

i started on the tutorials because of minecraft. I stayed because of Bucky!!!

[TheDiggster13]

I'm technically as likely to get 5 5 5 5 5 5 5 5 5 5 as I am to get 1 2 3 4 5 6 1 2 3 4 !

[idiotrun1997]

Is it possible to use the random generator to generate up to negative numbers?

[RMCxMODDERSx]

@idiotrun1997 Yes easily, make an array for negative numbers and count from negative numbers to whatever.

[IceAges14Aces]

Hey, I have a question:

Is JavaScript Math.random method to generate random events truly random or not??? I heard that random systems based on algorithms aren't truly random.....

[theXminecrafter]

I made a simple lottery using this

[PopulardayOfApril]

made a password creator that creates as long passwords as you need and uses all numbers and lower case letters and Upper case letters.

[knight11ind]

@PopulardayOfApril

can u post the code plz.?

[PopulardayOfApril]

@knight11ind Maybe i can send it or what?

[Sobieski1]

How considerate of you to add calming bird sounds in the background!

[marko4449]

okay im learning math O__O" dang this makes my head hurt T__T

[JKTCGMV13]

or just Math.Random()

[SprayedToTheBone]

@JKTCGMV13 Math.Random() only gives you a number from 0 through 1.

[vertoxz123]

Thanks!

[PPGaminGProductions]

wtf ^^ out aint workin for me ... is it out of memory thing?

[iblowmydad]

lol dice....

[xRobG]

Dude you generated my phone number at 3:54 ! WTF!

[TheWouter101]

@xRobG

since a phonenumber always starts with a zero, this isn't yours.

:)

[xRobG]

@TheWouter101 My phone number starts with 416, the area code is 1, but you never put area code when dialing locally. So this is my phone number.

[amermomani]

How do you generate a "double" random with a range (like from 4.6 to 8.3)

[sporreking]

Just 1 question, why did you type System.out.println(number + " ") ; instead of

System.out.println(number);?

[RaqibulHayder]

@sporreking System.out.println(number + " ") gives a space after the number. It shouldn't matter if you don't put it.

[EpicnessPivotMaster]

Man, you really should write a book about java... it's easier to study these stuff on books.

[sammyzeus]

You smoke?



[the314Qwerty]

i typed:

System.out.println("7,7,7,7,7,­7,7.");

and got '7,7,7,7,7,7,7.'!

must be a message

[tnagya]

This is the first video to hear Bucky opened the window. Check the birds chirp in the background. Must have been a good sunny day...

Later on (sometime in late autumn) check out for the crickets chirr...

Easier to catch with headphones on...

[Jesteria78]

sorry I meant number + 1

[Jesteria78]

you can also say number++ in your println... (yes, that is ugly) :)))

[baseball47347]

pretty a cool way to get that :---)

[bizaromatt]

int GetRandomNumber{

return 4;

}

// Perfectly Random.

[Naihatsu92]

Huh... I got 7 3s in a row... Neat.

[DarthLOL293]

I just got 2 5 5 0 2 2 5 0 2 0

ITS A CONSIPRACY!

[strawberryicedtea]

@DarthLOL293 this system relies on PC lag oso from what i heard :D

[cheaterhacker1]

for(int counter=1; counter<=1000;counter++){ number = 50+lol.nextInt(100); if(number <= 100) System.out.println(number);

[FullOfJavaBeans]

i prefer using

(random = rar)

int random =rar.nextInt(5)+1

[scrbluegaming]

RPG BATTLE SYSTEM :) if(dice + attack >= 5) { System.out.println("You have defeated the monster");

} else { System.out.println("You have lost and you were killed");

}

[preymouth]

Shit, now I have to find the Video4Winter comment.

[hizzleyo]

BUCKY FOR PRESIDENT

[seed419]

diyyuce

[HarrowedBeThyName]

For such a brilliant programmer, I figured you'd know that

clearingYourThroat =/= smokersCough

[izzatnadiri]

thanks dude!!!

[InvaderWakkoReborn]

I'm so bored I made a guessing game that lets you decide the number range you guess in, how many rounds you want to play, and gives a score based on how close you were to the number.

Now to add total score. :)

[InvaderWakkoReborn]

I used this to generate a random even number from 10-20:

number = (5+dice.nextInt(6))*2;

Not hard, but fun to mess around with. :)

[bor223]

i have got a bug! my output is not the same! 0_o

[GenericPlaque]

Why the balls wouldn't you teach us how to make a random number within a certain range?

It's an incredibly essential part of a random number generator.

[fopple13]

@GenericPlaque

He did teach you:

number = 1 + dice.nextInt(6) gives a random number from 1 to 6.

You can also have: number = 5 + dice.nextInt(6). This gives you a random number from 5 to 10.

[GenericPlaque]

@fopple13

There's a built-in function to do this in Java, and it's much easier to use. :/

[plutgamer]

thx!

im programming a class that can store an Integer in a way that you cant use a memory editor to cheat.

im using a system with random numbers.

[joannis11]

Cool, no seeding numbers :)

[emmetgb]

how to use a number generator

y = start posting lots of random shit.

x = put thing like "y =," and "x =,"

use this code :

.

[nutelina]

Do you do these tutorials while the weather is nice outside? Because I do hear birds singing in the background ; )

[unabomberman]

For some I reason, I find it funny that Bucky keeps promising us we're gonna become experts. He should totally put that on a shirt and sell it.

"You'll Be an Expert. I Promise."

[joannis11]

@unabomberman I think I would buy it :P

[ThePenguinio]

Don't smoke Bucky! We need your to keep making programming tutorials!

[joannis11]

@ThePenguinio Like you're reading my mind, even while you are in the past...

[smoothy023]

import java.util.Random;

public class apples {

public static void main (String[] args)

{ int bucky[]= new int[10]; int number; Random dice = new Random(); number = dice.nextInt(10); bucky[0]=87; bucky[1]=100; bucky[2]=150; bucky[3]=250; bucky[4]=2050; bucky[5]=142; bucky[6]=234; bucky[7]=141; bucky[8]=241; bucky[9]=2412; System.out.println(bucky[numbe­r]);

}

}

This actually selects a random number in the array wich outputs an array chosen by the random engine..

xo

[imodatlife]

meow

[PacketEditV75]

if you got "save problme

with reson "cp1255

You have a wired letter dot thats up

remove it,than the cp letter will remove

[b4llscr4tchm0d3]

i used the same coding as you but it gives me a fatal error O.o

[krechlich]

how can i count multiple random numbers together?

[Alek5andr]

Like tutorial VM >.<

Question:

what does mean this writing: SMT = random(int, int); ?

How toexplain two integer numbers in brackets?

Many thanks!

[ShakespearHD]

Bucky, Thanks for sharing :-)

[TheMoronKiller]

another example;

for (int i=0;i<10;i++){

 System.out.println(Math.rint(M­ath.random()*6));

}

[trelagato23]

its not outputting multiple numbers for me, only one number.

[Budishaa]

@trelagato23 do you have a loop?

[MrBlockersPro]

i love the birds in the background, and the relaxing sounds. (lol) nice touch! lawl

[kevinhc628]

I learned to use

int random = x * (int)(Math.random()*y) + z;

x = difference between each number in the set

y = how many numbers in the list to generate from

z = the lowest number possible to be generated

For example

int random = 4 * (int)(Math.random() * 5) + 6;

generates a number from {6, 10, 14, 18, 22}

[GohansRiceBall]

@kevinhc628 Thank you for this. One question: Why do you have (int) before Math.random?

I'm still pretty new to Java and have not seen that before.

[GohansRiceBall]

@kevinhc628 I figured it out. It's for casting since Math.random(); usually returns a double. Thanks for your comment again.

[kylemaster38]

i got different random numbers :P

[raibreakz]

you could also be number = dice.nextInt(6)+1;

[Moe1993x]

@raibreakz

sigh

[adanaz9]

Thanks for the simplicity.

[ben1996123]

import java.util.Random;

class Random_dice { public static void main(String args[]){ Random dice = new Random(); int number; for(int counter = 1; counter<=10; counter++){ number = 10+dice.nextInt(2); System.out.println("Bucky's Java tutorials score: " + number + " / 10"); } }

}

[ydantezs]

Спасибо большое! Очень помогло.

[wallycall]

What's the point of the quotes below?

System.out.println(number+ " ")

[carelessmorning]

@wallycall Nothing, just a mistake.

[MCPiciek]

int lol = Math.ceil(Math.random*10);

Wouldn't that be easier? No need to import stuff and it gives You a random number between 1 and 10.

[j3s0n]

@MCPiciek He wanted 1 through 6 to simulate a dice.

[MCPiciek]

@j3s0n I realized that after posting but I'm pretty sure I've seen somewhere someone using this method for numbers between 1 and 6.

[j3s0n]

@MCPiciek You might be able to. I can think of an algorithm that may work to limit the results to 1 and 6 with your method.