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How to print out string at random interval

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Join Date: Nov 2004

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George2

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How to print out string at random interval

Apr 7th, 2005

Hello everyone,

I want to print out the string "Hello World!" to console at a random interval, and the average length of the random interval is 1 minute when the string is printed out hundreds of times. Anyone know how to accomplish this?

Thanks in advance,
George

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Re: How to print out string at random interval

Apr 8th, 2005

I tried this out and here's the method I came up with... enjoy!

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
public class Rand
{
	public static void main(String[] args)
	{
		String[] sa = {"HelloWorld", " "}; // holds Hello World or just a blank string
		for (int i=0; i<60000; i++) // i think this loop takes aboout a minute
		{							// but im not sure
			int num = (int) (Math.random() * 2); // chooses a random number (0 or 1)
			System.out.println(sa[num]); // and then prints out the corresponding String
											// from above
		}
	}
}
public class Rand
{
	public static void main(String[] args)
	{
		String[] sa = {"HelloWorld", " "}; // holds Hello World or just a blank string
		for (int i=0; i<60000; i++) // i think this loop takes aboout a minute
		{							// but im not sure
			int num = (int) (Math.random() * 2); // chooses a random number (0 or 1)
			System.out.println(sa[num]); // and then prints out the corresponding String
											// from above
		}
	}
}

Nick Nisi

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tonakai

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Re: How to print out string at random interval

Apr 8th, 2005

it isnot very useful, since the loop can vary from CPU to CPU. Faster CPUs process the loop quicker...
another approch can be with creating a thread(timertask) and a timer class, check out API docs for more....

Last edited by tonakai; Apr 8th, 2005 at 3:14 am. Reason: add (timertask)

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George2

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Re: How to print out string at random interval

Apr 8th, 2005

Thanks tonakai,

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Originally Posted by tonakai

it isnot very useful, since the loop can vary from CPU to CPU. Faster CPUs process the loop quicker...
another approch can be with creating a thread(timertask) and a timer class, check out API docs for more....

Your reply is very helpful. Can you describe your idea of "another approch can be with creating a thread(timertask) and a timer class" in more details?

regards,
George

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Re: How to print out string at random interval

Apr 8th, 2005

Thanks stupidenator,

•

Originally Posted by stupidenator

I tried this out and here's the method I came up with... enjoy!
Help with Code Tags

Java Syntax (Toggle Plain Text)
public class Rand
{
	public static void main(String[] args)
	{
		String[] sa = {"HelloWorld", " "}; // holds Hello World or just a blank string
		for (int i=0; i<60000; i++) // i think this loop takes aboout a minute
		{							// but im not sure
			int num = (int) (Math.random() * 2); // chooses a random number (0 or 1)
			System.out.println(sa[num]); // and then prints out the corresponding String
											// from above
		}
	}
}
public class Rand { public static void main(String[] args) { String[] sa = {"HelloWorld", " "}; // holds Hello World or just a blank string for (int i=0; i<60000; i++) // i think this loop takes aboout a minute { // but im not sure int num = (int) (Math.random() * 2); // chooses a random number (0 or 1) System.out.println(sa[num]); // and then prints out the corresponding String // from above } } }
Nick Nisi

How can you draw the conclusion that the loop in your sample will takes about a minute?

regards,
George

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Re: How to print out string at random interval

Apr 8th, 2005

Here an example,
myTimer.java

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
import java.util.*;
 
public class myTimertask extends TimerTask {
  public void run() {
    System.out.println("Hello World!");
  }
}
import java.util.*;

public class myTimertask extends TimerTask {
  public void run() {
    System.out.println("Hello World!");
  }
}

myTimertaskUser.java

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
import java.util.*;
public class myTimerUser {
  public static void main(String[] args) {
    myTimertask testTimertask = new myTimertask();
    Timer testTimer = new Timer();
    testTimer.schedule(testTimertask,1000,1000);
  }
}
import java.util.*;
public class myTimerUser {
  public static void main(String[] args) {
    myTimertask testTimertask = new myTimertask();
    Timer testTimer = new Timer();
    testTimer.schedule(testTimertask,1000,1000);
  }
}

well after i write this, i see that it is not possible to change its display time directly, so you need to figure out some other way, like after displaying text, cancel the timer, then generate a new random number, then start again.... i can give you another example but, i am a bit lazy....

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duckman

Re: How to print out string at random interval

Apr 8th, 2005

•

for (int i=0; i<60000; i++) // i think this loop takes aboout a minute

It won't

On my machine at work (which is extremely slow because of lack of memory, it often spends 5 minutes swapping data when I switch applications) it took 2 minutes almost to the second.

Anyway, it won't print out strings with an average interval of one minute.
For that you need to use a Thread which sleeps for a random interval.
Of course you can't possibly create an unknown number of random intervals yet have those have an average time of a minute.
At best you can create a random number between 2 limits and use that as the interval where the average between those numbers is one minute (in milliseconds which is the measure of time used by Thread.sleep()).

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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Re: How to print out string at random interval

Apr 8th, 2005

I'm not really sure why I thought that loop would last for a minute. Sorry about that...

Nick Nisi

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Posting Whiz

Re: How to print out string at random interval

Apr 8th, 2005

to average one minute, I would use java.util.Random and do the following...

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
import java.util.Random;
 
class OneMinute
{
	public static void main(String[] args) 
	{
		double numSeconds, numSecondsTotal;
		Random random = new Random();
 
		numSecondsTotal = 0;
		for (int i=0; i<100; i++)
		{
			numSeconds = (random.nextFloat()+0.5)*60;
			numSecondsTotal += numSeconds;
			System.out.println(numSeconds);
		}
		System.out.println("The average number of seconds is: "+ numSecondsTotal/100);
 
	}
}
import java.util.Random;

class OneMinute
{
	public static void main(String[] args) 
	{
		double numSeconds, numSecondsTotal;
		Random random = new Random();

		numSecondsTotal = 0;
		for (int i=0; i<100; i++)
		{
			numSeconds = (random.nextFloat()+0.5)*60;
			numSecondsTotal += numSeconds;
			System.out.println(numSeconds);
		}
		System.out.println("The average number of seconds is: "+ numSecondsTotal/100);

	}
}

I tried usign nextGaussian() but there is no way to change the standard distrubution to something else, but anyways this should work, i tried it out and it always averaged between 58 - 61 seconds, but has a range of 30-90 seconds (aka 0.5 - 1.5 minutes). You can tweak with it a bit to get a bigger range (or smaller) if need be. Use this in conjuction with tonakai's post to get what u need.
http://java.brangle.com/tutorials/java/util/Random.php

Last edited by paradox814; Apr 8th, 2005 at 5:46 pm. Reason: removed unneeded code

http://www.brangle.com/

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Posting Whiz

Gaussian method for much bigger range

#10

Apr 8th, 2005

Ok so I got bored and decided to do the gaussian method, of course I kinda forced it to do what i wanted with the if statement in there, but either way this has a much much bigger range of 0 - 120 seconds

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
import java.util.Random;
 
class OneMinute
{
	public static void main(String[] args) 
	{
		double numSecondsTotal;
		double i=0, numSeconds =0;
		Random random = new Random();
 
		numSecondsTotal = 0;
 
		do
		{
			numSeconds = (random.nextGaussian()+1)*60.0;
			if (numSeconds >= 0.0 && numSeconds <= 120.0)
			{
				i++;
				numSecondsTotal += numSeconds;
				System.out.println(numSeconds);
			}
		}
		while (i < 100);
		System.out.println("The average number of seconds is: "+ numSecondsTotal/100);
 
	}
}
import java.util.Random;

class OneMinute
{
	public static void main(String[] args) 
	{
		double numSecondsTotal;
		double i=0, numSeconds =0;
		Random random = new Random();

		numSecondsTotal = 0;

		do
		{
			numSeconds = (random.nextGaussian()+1)*60.0;
			if (numSeconds >= 0.0 && numSeconds <= 120.0)
			{
				i++;
				numSecondsTotal += numSeconds;
				System.out.println(numSeconds);
			}
		}
		while (i < 100);
		System.out.println("The average number of seconds is: "+ numSecondsTotal/100);

	}
}