Computer Science Canada

Generating Multiple Random Numbers
Author:  Flashkicks [ Thu Feb 10, 2005 1:35 pm ]
Post subject:  Generating Multiple Random Numbers
This is an assignment I have, and the following is the coding. I can not get the "generate 5 random numbers between 1-10" part. [Just ignore the other stuff.. sqrRoot, absolute..etc..] Any help would be nice. I have my program to work, yes; but I think java should be far more capable of figuring out mulitple values in one line rather than having to write it out 5 times. I mean, even Turing just simply uses a for statement.. Can someone tell me how I would use a "for statement" for this?
code:
// The "PowerExample" class.
public class PowerExample
{
    public static void main (String [] args)
    {
        // declare variables
        int valueOne, valueTwo;
        double answer, randomValue1, randomValue2, randomValue3, randomValue4, randomValue5;

        //initialize
        valueOne = 4;
        valueTwo = 12;

        //use Math class to find 4^12
        answer = Math.pow (4, 7);
        System.out.println (answer);

        System.out.println (Math.sqrt (12)); // square root of 12

        System.out.println (Math.abs (4 - 12)); // absolute of 4-12

        /* Math.random () */

//  this whole secion here..  This is Ugly!
        randomValue1 = ((Math.random () * 10) + 1); // displays 5 random nums
        randomValue2 = ((Math.random () * 10) + 1); // displays 5 random nums
        randomValue3 = ((Math.random () * 10) + 1); // displays 5 random nums
        randomValue4 = ((Math.random () * 10) + 1); // displays 5 random nums
        randomValue5 = ((Math.random () * 10) + 1); // displays 5 random nums
        System.out.println (randomValue1 + "  " + randomValue2 + "  " + randomValue3);
        System.out.println (randomValue4 + "  " + randomValue5);
    } // main method
} // PowerExample class

//experiment with the various methods in the Math class.

//1.  Find the square root of 12
//2.  Find the absolute value of 4 - 12
//3.  Declare a real (double) variable randomValue.  Your program should display five random values between 0 and 10.
//4.  Find 5 random values between 11 and 95
//5.  Make up two questions and display the answer.


~Flashkicks
Author:  Tony [ Thu Feb 10, 2005 1:40 pm ]
Post subject: 
Java:

for(int i=0;i<5;i++)
     randomValue[i] = ((Math.random () * 10) + 1);


btw, if you want all 5 digits in a single statement, you can pick a random numbet between (10000 and 99999) and split it up by digits Wink
Author:  Flashkicks [ Thu Feb 10, 2005 1:49 pm ]
Post subject: 
Wow I think thats the fastest reply Iv ever seen Shocked .. Thanks once again Tony. Your the man Wink..lol. I shall go try it and I think it will work. I was just playing around with the for loops myself but I couldnt get it to work. So then I tried something called a "while loop" or something.. Still no luck.. But thanks man! I appreciate it!
~Flashkicks

:: UpDated ::
Okay- Tony. I am sorry but it is still not working.. Says randomValue is not an array type. I changed it to int and whatnot [also got rid of the randomValue1, and randomValue2 etc] and nothing will work.. Do you think you could try editing it into my program?. I am sorry to bug you. I shall keep trying..

::: UpDated AGAIN :::
Okay I am sorry to do this but I got it to work.. It was very simple. however, if you look below I am supposed to now do between 11-95 .. THAT--is where I am stuck. I pulled out the ol' reference book and everything. So please.. Someone help..lol This is why i hate Java. Iv always hated Java and I still say its EVIL!!!
Author:  Tony [ Thu Feb 10, 2005 3:21 pm ]
Post subject: 
Java:

int randomValue[4];

for(int i=0;i<5;i++)
     randomValue[i] = ((Math.random () * (95-11)) + 11);
Author:  wtd [ Thu Feb 10, 2005 3:57 pm ]
Post subject: 
tony wrote:
Java:

int randomValue[4];

for(int i=0;i<5;i++)
     randomValue[i] = ((Math.random () * (95-11)) + 11);


That's just asking for problems. There's only room for 4 values in that array, but you run the loop 5 times.

Java:
// Java 1.5

import java.lang.*;
import java.util.*;

public class RandomNumbers
{
  public static void Main()
  {
    ArrayList<Integer> randomValue = new ArrayList<Integer>(5);
    for (int i = 0; i < 5; i++)
      randomValue.add((Math.random() * (95 - 11)) + 11);
  }
}
Author:  Tony [ Thu Feb 10, 2005 4:28 pm ]
Post subject: 
aren't Java arrays 0-index? (0,1,2,3,4 ~ 5 elements).

anyways, wtd knows what he's doing. I'm just stabbing in the dark (haven't actually done any Java or even C++ for that matter in a while)
Author:  wtd [ Thu Feb 10, 2005 4:42 pm ]
Post subject: 
tony wrote:
aren't Java arrays 0-index? (0,1,2,3,4 ~ 5 elements).


Yes, but the number you give in the declaration/initialization is the capacity of the array, not the last index.

Of course, I'd still prefer Ruby.

code:
randomValue = Array.new(4) { rand * (95 - 11) + 11 }
Author:  Flashkicks [ Fri Feb 11, 2005 10:14 am ]
Post subject: 
Kay I tried all of your guys' stuff and some of it wasa a bit complicating, while other stuff did kinda work.. So I took your coding and changed it a tad bit and now I got it working. Heres what I used:
code:
for (int i = 0 ; i < 5 ; i++)
            System.out.println ((Math.random () * (84)) + 11); // Prints out 5 random numbers [11-95]


And this did the job fiiine Wink
Thanks for all your help~
~Flashkicks
Author:  wtd [ Fri Feb 11, 2005 2:59 pm ]
Post subject: 
Flashkicks wrote:
Kay I tried all of your guys' stuff and some of it wasa a bit complicating, while other stuff did kinda work.. So I took your coding and changed it a tad bit and now I got it working. Heres what I used:
code:
for (int i = 0 ; i < 5 ; i++)
            System.out.println ((Math.random () * (84)) + 11); // Prints out 5 random numbers [11-95]


And this did the job fiiine Wink
Thanks for all your help~
~Flashkicks


Note: while it may be good Turing style to put space between a function/procedure and the parens that follow it, the more generally accepted style for Java/C/C++/etc. is for there to be no space. Additionally, you can remove a number of parens due to the order of operations. Multiplication is performed first, then addition.

code:
for (int i = 0 ; i < 5 ; i++)
            System.out.println(Math.random() * 84 + 11);

:


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