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generating random numbers into an array..

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Join Date: Jul 2005

Posts: 19

Reputation: JavaFish is an unknown quantity at this point

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JavaFish

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Newbie Poster

generating random numbers into an array..

Jul 28th, 2005

Hi

I have searched this site for help with this and used an example of a lottery numbers program.

However, I need to modify it slightly but can't seem to get it right.

I would like to be able to generate random numbers between 0 and 100 (maybe negative oness as well). The code below just generates 7 numbers between 0 and 6 and I can't see where I need to adjust the code. If anyone could help me with this, I would be really grateful, even just an explaination so I can work it out myself would be great as I just can't see where it is saying only use those low 0 - 6 digits! :rolleyes:

// random number generator

import java.lang.Math;
// setting up array with random numbers 26 july 2005

public class myRandomNodes {
public static void main(String[] args)
{
new ranNumbers (7);
}
}

class myRanNumbers {
private int[] numbers;

public myRanNumbers (int n )
{
numbers = new int[n];

// initialise numbers
int i = 0;

while (i < n ) {
//int r = (int) (Math.random() * n);
// create a random integer between 1 and 100 inclusive
int r = (int) Math.floor(Math.random() * 100);

if (add (numbers, i, r)) {
++i;
}
}

show_all (numbers);
}

private boolean add (int [] list, int size, int val)
{
for (int i = 0; i < size; i++ ){
if (list[i] == val) {
return false;
}
}
list[size] = val;

return true;
}

private void show_all (int[] list)
{
for (int i = 0; i < list.length; i++ ) {
//System.out.print(list[i] + " ");
System.out.println("rounded number between 0 and 100 is ");

}
System.out.println();
}
}

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Join Date: Nov 2004

Posts: 6,143

Reputation: jwenting is just really nice

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jwenting

Offline

duckman

Re: generating random numbers into an array..

Jul 28th, 2005

1) use code tags
2) follow the Sun coding standards, which you can get from Sun.

Doing both will make your code a lot easier to read and debug, as it stands I'm not even going to try.

As people are clearly allowed to attack me but I'm not allowed to defend myself, I no longer post to this site.

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Join Date: Jul 2005

Posts: 19

Reputation: JavaFish is an unknown quantity at this point

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JavaFish

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Newbie Poster

Re: generating random numbers into an array..

Jul 28th, 2005

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
 
// random number generator
 
import java.lang.Math;
 
 
public class myRandomNodes 
{
   public static void main(String[] args)
   {
     new ranNumbers (7); 
   }
}
 
  class myRanNumbers 
  {
    private int[] numbers;
 
    public myRanNumbers (int n )
    {
      numbers = new int[n];
 
      // initialise numbers
      int i = 0;
 
      while (i < n ) 
      {
        int r = (int) Math.floor(Math.random() * 100);
        if (add (numbers, i, r)) 
        {
          ++i;
        }
      }
 
     show_all (numbers);
   }
 
   private boolean add (int [] list, int size, int val)
   {
     for (int i = 0; i < size; i++ )
     {
       if (list[i] == val) 
       {
         return false;
       }
     }
   list[size] = val;
 
   return true;
   }
 
   private void show_all (int[] list)
   {
     for (int i = 0; i < list.length; i++ ) 
     {
     System.out.print(list[i] + " ");
     }
     System.out.println();
     }
  }
// random number generator

import java.lang.Math;


public class myRandomNodes 
{
   public static void main(String[] args)
   {
     new ranNumbers (7); 
   }
}

  class myRanNumbers 
  {
    private int[] numbers;

    public myRanNumbers (int n )
    {
      numbers = new int[n];

      // initialise numbers
      int i = 0;

      while (i < n ) 
      {
        int r = (int) Math.floor(Math.random() * 100);
        if (add (numbers, i, r)) 
        {
          ++i;
        }
      }

     show_all (numbers);
   }

   private boolean add (int [] list, int size, int val)
   {
     for (int i = 0; i < size; i++ )
     {
       if (list[i] == val) 
       {
         return false;
       }
     }
   list[size] = val;
 
   return true;
   }

   private void show_all (int[] list)
   {
     for (int i = 0; i < list.length; i++ ) 
     {
     System.out.print(list[i] + " ");
     }
     System.out.println();
     }
  }

Hope it makes it a bit easier to read - sorry about the unformatting before :-|

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Join Date: Jun 2004

Posts: 2,108

Reputation: server_crash is on a distinguished road

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server_crash server_crash is offline

Offline

Postaholic

Re: generating random numbers into an array..

Jul 28th, 2005

Use the Random Class. It's more random than Math.random();

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
import java.util.*;
 
public class RandomClassTest
{
	public static void main(String[] args)
	{
		Random randNumGenerator = new Random();
 
		int[] x = new int[7];
		for (int i=0; i<x.length; i++)
		{
			x[i] = (randNumGenerator.nextInt(100)+1);
		}
	}
}
import java.util.*;

public class RandomClassTest
{
	public static void main(String[] args)
	{
		Random randNumGenerator = new Random();

		int[] x = new int[7];
		for (int i=0; i<x.length; i++)
		{
			x[i] = (randNumGenerator.nextInt(100)+1);
		}
	}
}

Be sure to add 1 if you want to reach 100.

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Join Date: Jun 2004

Posts: 609

Reputation: freesoft_2000 is an unknown quantity at this point

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freesoft_2000 freesoft_2000 is offline

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Practically a Master Poster

Re: generating random numbers into an array..

Jul 29th, 2005

Hi everyone,

•

Originally Posted by server_crash

Use the Random Class. It's more random than Math.random();
Help with Code Tags

Java Syntax (Toggle Plain Text)
import java.util.*;
 
public class RandomClassTest
{
	public static void main(String[] args)
	{
		Random randNumGenerator = new Random();
 
		int[] x = new int[7];
		for (int i=0; i<x.length; i++)
		{
			x[i] = (randNumGenerator.nextInt(100)+1);
		}
	}
}
import java.util.*; public class RandomClassTest { public static void main(String[] args) { Random randNumGenerator = new Random(); int[] x = new int[7]; for (int i=0; i<x.length; i++) { x[i] = (randNumGenerator.nextInt(100)+1); } } }
Be sure to add 1 if you want to reach 100.

Could not have said it better myself

Richard West

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Doesn’t that sound like "Ein Volk, Ein Reich, Ein Führer" to you, too?
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