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Java Collection Q&A » array » random 

1. How do I randomly fill an array in Java?    stackoverflow.com

I'm writing a program that creates a 2D array from a integer n. I then have to fill the array with values from 1 to the n*n array size and check ...

2. how to generate random number from array    stackoverflow.com

How to generate random number from an array? and not from a range.

int n [] = {1,7,3,5,8,10,33,12,18}

3. How to do a random-and-unique generator?    stackoverflow.com

I already wrote a random generator which take arguments a and b, where a is minimun and b is maximum value, like this randomGenerator(int a, int b) What I want to do ...

4. How to generate numbers from an array randomly,with each number being unique    stackoverflow.com

I hav a numeric array,which contains 20 elements.I am displaying the numbers randomly for a blackberry application,bt i want dat all d numbers generated should b unique.It should b randomly generated,bt ...

5. A random generator for array indices..?    stackoverflow.com

i know this for normal integers, but is there for such a thing as indices

Random Dice = new Random();
int n = Dice.nextInt(6);
System.out.println(n);

6. Random Generated word changes when flipping between portrait and landscape    stackoverflow.com

I have an array in res/values/array.xml.

<string-array name="list">
    <item>string 1</item>
    <item>string 2</item>
    <item>string 3</item>
</string-array>
And this is my Java-Code without the import-statements.
public class ...

7. drawing random circles, storing their coorindates in an array    stackoverflow.com

For homework I want to draw circles randomly around the screen. If any of the circles overlap, then I want to fill in those circles. I am starting with some code ...

8. RandomizedQuickSort method for arrays    stackoverflow.com

IS there RandomizedQuickSort method in java API? OR we should write its code ourselves? thanks

9. draw random circles, first storing the points in an array    stackoverflow.com

This is what I want to accomplish for homework: Design and implement a program that draws circles, with the radius and location of each circle determined at random. If ...

10. How Can I Display a N x N Matrix of Random Numbers in Java?    stackoverflow.com

I'm trying to create a matrix of random double numbers. The matrix must be of size n x n and all numbers must be between 1 and 100. I've been trying ...

11. drawing random circles, storing their coorindates in an array    stackoverflow.com

This is what I want to accomplish for homework: Design and implement a program that draws circles, with the radius and location of each circle determined at random. If a circle ...

12. java random array    stackoverflow.com

i would like to make the question random, and when i give the answer to compare if they are correct answer or not?? can someone give me a little help with it?


import ...

13. Generating random words in Java?    stackoverflow.com

I wrote up a program that can sort words and determine any anagrams. I want to generate an array of random strings so that I can test my method's runtime.

public static ...

14. Java Array help    stackoverflow.com

I require help with a small Java problem I am having. I have an array called lowest. An example entry of lowest would be [6 2 9 2 7 2 3]. What ...

15. Java random array of numbers    stackoverflow.com

I am trying to make an array of random numbers that range from 0-9 with the variable for this one being kickerNumbers. I get a compile error though saying incompatible ...

16. Pick random element from array, but unique    stackoverflow.com

I have array of countries. I want to pick 5 random countries from my array list, but I want them to be unique. This is what I have so far:

String allCountries[] = ...

17. Generate Random numbers in array, add them together and store the answers in array    stackoverflow.com

I am new to Java and trying to solve the problem below So this is my story: Program generates 20 numbers up to 100 and stores every number in array. Once generated the ...

18. Java: How to randomly go through an array?    stackoverflow.com

I have an array of size x and I need to go through the list randomly but getting to each element once. What is the most efficient way to do this? ...

19. Array to generate 30 random numbers from 1-300 returns all 0s instead of other numbers    stackoverflow.com

I have a problem where I'm trying to fill an array with 30 random integers from the range 1-300 with just a main method and one more method called LOAD(). For ...

20. print an array in random order    stackoverflow.com

how to print an array in random order in java? example: int[] myArray = {5,4,3,2,1}; when printed, result should possibly be: 3 2 1 4 5 or 4 3 2 5 1

21. NPC movement in the array - pre-defined    stackoverflow.com

I need to create an object of a hunter(NPC) which will be moving from 12,12 to 0,0 point using a random path, each movement per player movement, this is my code ...

22. How to add a variable to an array    stackoverflow.com

I am trying to set the value in an array to a variable. Here is my code:

//init the array as a float
//I have tried to put a value in the brackets, ...

23. Math.random and Arrays    bytes.com

jca613 this what i got so far. i understand arrays and Math.random i think,but i need to use Math.random and arrays to make 100 random integers between 1 -9 what am ...

25. Selecting a random element from an anonymous array    coderanch.com

I know that this may not be the clearest code in the world, but when I came across it in a book I thought it was pretty nifty. Please take a look at the following: char c = new char[] {'a', 'b', 'c', 'z'}[(int)(Math.random() * 4)]; It will grab a random array element from the anonymous array & assign it to ...

26. random numbers in arrays    coderanch.com

Howdy folks, Is it possible to email a short program to someone for assistance in debugging it? It is supposed to generate random numbers and place them into an array, making sure that no numbers are repeated. Then it is supposed to convert these numbers to string and set them as text in an array of TextFields. It will compile, but ...

27. Random numbers and arrays    coderanch.com

Howdy folks, Let's try this again. This is a small program which is "supposed" to generate 3 random numbers from 1 to 6, not allowing any duplicates. Then it should put these numbers into an array of TextFields. It compiles but gives an exception in thread "main" NullPointerException. I figure that there is a problem with one of the arrays, but ...

28. Randomly shuffling an array.    coderanch.com

Hi all, I've racked my brains and torn the SDK documentation apart, but I can't find a way of randomly shuffling an array (in my case, it's an array of String objects - so that they display in a different order each time they're used). I found a way of shuffling a List item, but I'm damned if I can find ...

29. Random Numbers for Arrays??    coderanch.com

I am having trouble getting the code below to do what i want. I need the code to randomly generate a number between 0 and 45, if the number is between 0 and 45 it will place it in the array. But how do I make it generate another number if the one before it is not between 0 and 45??? ...

30. storing random no in Array...wiDout repetition    coderanch.com

Hi, I wana store random numbers in an Array without repetition...pleade guide me how to do it.... I am using the logic given below, but it does'nt work.... public class RArray{ public static void main(String args[]){ int arr[]=new int[15]; int i=0; for(i=0;i<=14;i++){ arr[i]=(int)(Math.random()*15)+1; for(int j=0;j<=i;j++){ int num=(int)(Math.random()*15)+1; if (arr[i] == arr[j]){ i--; } else{ arr[i]=num; } } } System.out.print("\n\n"); for(int k=0;k<=14;k++){ ...

31. array of random numbers    coderanch.com

Hi I have managed to get an array to generate random numbers between 0 and 99. However, I would also like the array to contain negative numbers as well but cannot work out how to do this? Anyone able to offer advise on this please? My code is: public class Random { public static void main(String[] args) { int amount = ...

32. selecting random elements from an array    coderanch.com

33. Making an array with random numbers    coderanch.com

Hello again. I am currently working with arrays and array lists. I want to make a seven point array, all of which will be a random number. Each of these will represent a temperature. The Code Is Here: import java.util.Random; public class ArrayOfTemperatures { public static void main(String[] args) { /* Create the array */ Random randomgenerator = new Random(); int[] ...

34. Searching through an array to find and print duplicate random numbers    coderanch.com

With the current code setup the print statement which states which numbers were duplicates is looped within the 1000 array? And when I bring it outside the first set of brackets it says its unable to find the variable i so how do I get that fixed? Any recommendations on how to remove that outside the loop but still have it ...

36. Assigning random numbers to an array    coderanch.com

(this is within a loop btw) Yeah, it may have been a good idea to show the array. And the init of the nums array. As it is not that clear what the code does. Now I understand what it does, but I don't know how it does it. For example, how does it make sure the same number isn't assigned ...

37. Java 6: Need to have an array of images of which I can randomly select    coderanch.com

Hello, I am trying to make an application that tests for color blindness, in which a person doing the test is seeing a picture with a number obscured in it. In the most ideal situation I have the pictures in a folder, which the application picks up when starting up. These images would then be held in an array, and each ...

38. Using arrays to randomly generate images? (applet)    coderanch.com

I'm trying to randomly generate a few images from a directory of images, but I have no idea how to do it. This is what I have without the random image generation component: import java.applet.Applet; import java.awt.Image; import java.awt.Graphics; public class applet2 extends Applet { Image card1, card2, card3, card4, card5, card6, card7, card8, card9, card10, card11, card12; // image variables ...

39. Array of instances using Math.random()    java-forums.org

import java.util.*; public class RandomNumbers { private static final int ARRAY_SIZE = 100; private static final int RAND_MAX = 1000; private Random random = new Random(); private int[] randomNumbers = new int[ARRAY_SIZE]; private int randNum; public void go() { for (int i = 0; i < ARRAY_SIZE; i++) { randNum = random.nextInt(RAND_MAX)+1; randomNumbers[i] = randNum; } } public static void main(String[] ...

40. Random numbers and arrays    java-forums.org

Hi, I'm new to writing java and am having a bit of trouble writing a program and would really appreciate some help :) Im trying to make a program that creates an array of 20 random integers between 0 and 99, then allows the user to enter a number (N) between 0 and 99 so that it (the program) can tell ...

41. Java program problem.. Arrays.. Random Numbers    java-forums.org

Hey guys and girls, i have my array program up and running fine (which is a random number generator 1-999) but im finding the last bit of my program quite difficult, im new to java and if an experienced java programmer could give me some advice or hints then i would appreciate it greatly. what i need to do is :- ...

42. LUDecomposition, random arrays.    java-forums.org

Hello! I'm Spanish and I'm studying 1st Year of Physics, I've started to use Java this year (we work with NeatBeans) and I'm having many problems with numerical techniques. I have to do a program that solves systems of N-equations by using the LUDecompositionImpl. What I have to do is to assign random values to each matrix. The problem is I ...

43. Math.random in array and reverse order    java-forums.org

import java.util.*; class RandomNumbers{ public static void main(String[] args) { Scanner scan = new Scanner(System.in); int n; int [] array = new int[n]; System.out.print("Enter the number of random numbers: "); n = scan.nextInt(); System.out.println("Here are the "+n+" random numbers:"); for(int a=0; a

44. Store Random numbers into Array    java-forums.org

package w2_2; import javax.swing.JOptionPane; import javax.swing.JTextArea; import java.util.Random; public class w2_2 { public static void main(String args[]){ Random dice = new Random(); int Dice1; int Dice2; int number; int store[]; store = new int[11]; for (int counter=1; counter<=10; counter++){ Dice1 = 1+ dice.nextInt(6); Dice2 = 1+ dice.nextInt(6); number = Dice1+Dice2; store[counter] =number; System.out.println(number); } System.out.println("Array at 3rd pt: is " + ...

45. Help with random bits array    java-forums.org

Not sure what your restrictions are here. Your code sort of implies that you want random integers of value 0 or 1 only. Since everything in a computer is composed of bits (8 to a byte, etc) then any random integer will be made up of random bits. Can you explain your problem more.

46. How to use arrays with Math.random    java-forums.org

Introduction: hi, im lenny from sweden and i've been studying java for almost 2 weeks! i'm wondering how i can assign values to an array, 0 = heads and 1=tails and use math.random to randomize the arrays to make it a 50-50% chance. public class Krona { private String heads, tails; private String throw[]; public void throw(){ throw= new String[1]; throw[0]=heads; ...

47. Fill array with random number, but elements cannot be duplicated    java-forums.org

say we have, int a[]=int a[5]; how do we fill 5 elements i.e 1,2,3,4,5 randomly in a[i](where i=0..4). using for loop. example a[0]=4 a[1]=2; a[2]=3; a[3]=5 a[4]=1 I was practicing arrays. I came up with this thought but i couldn't figure it out. I can fill random number using for loop, but random number generates duplicate number.I was trying to figure ...

48. Array of random numbers ...    java-forums.org

import java.util.Random; public class ArrayRandom{ public static void main(String args[] { Random r = new Random(); int temp; int arr[] = new int[50]; for(int i = 0; i < 50; i++) { temp = r.nextInt(999) + 1; // this will give you a random number between 0 to 999. arr[i] = temp; //here we know that the number is unique, so ...

49. Getting random word to print out in an Array    java-forums.org

Java Code: import java.util.Random; public class Dictionary{ public static void main(String[] args){ //Declaring a variable //Build an array of words {String words[] = new String[23]; words[1] = "dictionary"; words[2] = "restaurant"; words[3] = "televiion"; words[4] = "responsible"; words[5] = "technology"; words[6] = "collection"; words[7] = "communicate"; words[8] = "automobile"; words[9] = "federation"; words[10] = "enterprise"; words[11] = "exaggerate"; words[12] = "cappuccino"; ...

50. Pick random array index and change the element value    java-forums.org

Supposin' you have an array {1,2,3,4,5,6,7,8,9,10}. Also supposin' you want to randomly pick an index in that array and set the element of that random index to the value of 5. Now, simply print out the number of the changed index and: Lastly Supposin' you then want to add up all the elementsof the changed array to get the sum. example: ...

51. choosing random array to print to screen    java-forums.org

import java.util.Random; public class test{ public static void main(String[] args){ //test and test2 are pointers. int[] test = {1, 2, 3, 4}; int[] test2 = {1,2,3}; Random rand = new Random(); for (int x=0;x

52. Pick a random value from array?    java-forums.org

public class Fad { public static String[] communicationMethods = { "Facebook", "Phone", "SMS", "MSN" }; public static String name = ("Fad"); public static String mood; public static int lastSpoken; // last spoken in days public static boolean spokenRecently; public static boolean bored; public static boolean shouldSendMessage; public static void main(String[] args) { checkLastChat(); communicate(); } public static void checkLastChat() { if ...

54. Random automation of sports teams (things) using arrays, scanners, and randomNumbers    java-forums.org

So I was inspired by an example in my java 2 textbook and I have an idea for a java program but I'm not sure what the best approach would be. The example in the book is a program that deals a deck of 52 regular playing cards in a random order until the deck is empty using card objects. Basically ...

55. HELP! not sure how to create random Array    java-forums.org

56. Need help with random arrays    java-forums.org

Hello I've been trying to make a file for random arrays for my class. The problem I've been having is getting the mean on the random arrays of numbers. This is the code for my work. import java.util.*; public class TextLab06 { public static void main(String args[]) { System.out.println(); System.out.print("Enter the quantity of random numbers ===>> "); int listSize = Expo.enterInt(); ...

57. Placing unknown number of randomly generated numbers into an array.    forums.oracle.com

So, to print the contents of the array I remove the i-th index of the array so its n[] instead of n? I've tried a couple of variations where I remove "i" or the 0 in i = 0. From what you said I'm thinking it supposed to look like one of the following lines.

58. array of unique random numbers - help?    forums.oracle.com

basically, i'm trying to create a BINGO card. i stared learning Java a week ago and am finding it easy to learn and use....at least so far. my instructor gave me the assignment to created a BINGO card. so i used the system.out.format command to make 5 tab fields, 8 spaces each ("%8s %8s %8s %8s %8s", "B", "I", "N", "G", ...

59. Arrays and Random    forums.oracle.com

61. Random numbers into arrays    forums.oracle.com

62. randomly assigning values to an array    forums.oracle.com

Hi...im not 100% sure of what ur trying to do...but what i usually do is, take the cases array, fill all the slots with the NULL value, and then randomly overwrite the NULL values with values randomly selected from the money array...At least by adding NULL, u can check if the slot has been previuosly filled or not...Hope that was helpful... ...

63. creating an array to store random cards, ensuring there are no duplicates    forums.oracle.com

The normal way of doing something like this is to put the ordered values in a java.util.List, and then use java.util.Collections.shuffle() to shuffle it. That way you don't get dups. My guess is that your teacher is making you do this in a weird way so you have to put some effort into it.

64. random numbers and bubble sort with array    forums.oracle.com

65. Can I use math.random to select a position from an array?    forums.oracle.com

im trying to make a game of chance where the user will get a RANDOM message from clicking on a clickable box. I made the array of messages. Im just curious if Im allowed to use math.random on the array to pick out a random position number? is this possible? I know I can probably use the shuffle code or random.util ...

66. array question..can i randomly select a value    forums.oracle.com

I'm trying to make a mini slots game where the user will "push the handle" and the computer will pick a number from 3 separate arrays.Of course, related arrays will be in play to see if the numbers match. My question: Is it possible to pick a position randomly from an array? So if there's an array of ints, is there ...

67. Array random problem    forums.oracle.com

68. loading an array using math.random    forums.oracle.com

Exactly the same as loading any array with any data. To add: Do you know haow to access an array and a specific location in an array? Do you know how to make an assignment? If so then it seems the only problem would be generating the random numbers. See the Random class. Edited by: flounder on Dec 11, 2009 10:35 ...

69. Help with Unique Random Number Generator Array    forums.oracle.com

There are two approaches you can take: 1. Fill an array or List of 1000 elements with numbers 0-999. Shuffle it using Arrays.shuffle or Collections.shuffle. Iterate over the first 100 elements to select your random numbers. 2. Generate random numbers, and each time you generate one, check if it's already been generated. If so, do not increment your counter, because you ...

71. Random arrangement of array    forums.oracle.com

Hi I need to arrange numbers 1 to 9 randomly. Each time I run the program it should generate all numbers 1 to 9 but each time in a different random sequence. Random class helps to generate numbers in range 1 to 9 but does not gaurantee unique occurance of each number after i generate 9 numbers.. Pl help Thanks RV ...

72. Random Array    forums.oracle.com

73. Arrays+Math.random    forums.oracle.com

You're not following the pre and post conditions indicated in the code comments. setUpDictionary should be initializing a member variable secretWords. getNextWord should not call setUpDictionary because its precondition states that it has already been called. It should just use the member variable secretWords. You should also review how to call methods and access arrays, since you seem to be trying ...

74. Randomly choosing from an array    forums.oracle.com

EDIT: Just ran the program a BUNCH of times, and actually one time it came up with a word that was in my text file. The method I used to counting must not be correct thus making my array a lot bigger than it needs to be. Edited by: BAR7MAN on May 3, 2010 5:49 PM

75. Random numbers from an array?    forums.oracle.com

76. Random number from array?    forums.oracle.com

You could use the [Random|http://java.sun.com/javase/6/docs/api/java/util/Random.html] class to get a random number between 0 (inclusive) and (Array.length + 1) (exclusive) and then return the value in that array element. However, if you do this it really doesn't make much sense, as you could just use the random number that you got from the Random class. Alternatively, you could do a Google search ...

78. unique random array    forums.oracle.com

You don't say what symbol your compiler cannot find which is always a good start for getting help, but I see that you only say shuffle(deck). What class has shuffle as a static method? In the line above you correctly call a static Arrays method. Also, you say Collections.toArray. This is not a static method of Collectoins, but a regular one ...

79. Random Array Project Help.    forums.oracle.com

80. random array.    forums.oracle.com

so am assuming you were not asked to store unique values if you were you should just add values of r.nextInt(100); into one of javas collection framework that does not collect duplicate values so when ever the collection is 20 it would contain all unique values afterwards you add the contents of that to the array of int you would use ...

81. writing random array positions to file    forums.oracle.com

Hi all. I have an array of 1000 positions each consisting of a String. I want to write the strings equally to two seperate text files which i have managed without any probs. The problem is i want to write these strings in a total random order so each time its run different strings would end up in different files and ...

82. Help with arrays and random numbers    forums.oracle.com

System.out.println("Please ask the magic 8-ball your question"); /*System.out.println("Please ask the magic 8-ball your question"); System.out.println("Please ask the magic 8-ball your question"); System.out.println("Please ask the magic 8-ball your question"); System.out.println("Please ask the magic 8-ball your question"); */ Scanner in = new Scanner(System.in); String enterNum = in.next(); random_num newNum = new random_num(); String[] groups = null; groups[2] = "Please do not disturb me ...

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