Java Math Class

Looking for a math class method to calculate prime numbers up to 1000 and also perfect numbers up to 1000. Anybody know if one is available ?

You can try the following if you think it might help:public class MyMaths extends Homework {
    public static int[] primesUpToN(int n) {
        researchTopics.add("Eratosthenes' Sieve");
        researchTopics.add("Prime Numbers");
        addKnowledge(researchTopics.performResearch());
        Algorithm al = codeAlgorithm(knowledge, skills, resources);
        while (!al.testsSuccessful()) {
            Bug bug = al.debug().getNextBug();
            bug.quash();
        return al.apply(n);
    public static void main(String[] args) {
        System.out.println(primesUpToN(1000));
}-- Scott

Similar Messages

Using java math class for power's SQ rt and rounding.

Hey all
ive attempted to use maths class to create a program a user can enter a number and then the output shows
The number rounded to the nearest integer
The Square root of the number
and finaly the number to the power of 6
So far i have the following code but im a bit thick to what im missing ....
import java.util.*;
public class Mathclass
     public static void main(String[] args)
     Scanner kybd = new Scanner(System.in);
     double num = kybd.nextInt(); // kybd is an instance of Scanner
     public static double ceil (double num);
     public static double sqrt (double num);
     public static double exp (double num);
}}Please be kind i know the outputs arnt there yet but im getting 15 errors in javac
Thankyou

Javaman01 wrote:
i can understand that you feel this way , i just have a lot of programs i need to complete for a portfolio tommorow , so i need all the help i can get.Well, then I guess you started too late. Talk to your teacher that you won't be able to get it done on your own. Start learning your course book or the basic tutorials I posted and try to do the assignments again. I really think you know too little to get this done.
Javaman01 wrote:
if you wish not to help the please dont comment as i fear this will put others of helping me when i need it most.I did help you! And you have nothing to say about me posting here or not. Just as I can't stop you from trying to get others to do your homework.
Javaman01 wrote:
thankyouYou're welcome.

Simple integer generation using java math classes

I want to generate a integer which should be combination of 2 integer and one int
and anytime I call generate it should generate same value for same input and for different combinations it should generate different value.
for example I passed to the service two integers 24, 25 and one int 76
assume it generated 242576
I restart jvm to the service pass the same values mentioned above it should return me same output 242576.
I want to do this using some math functionality not using string concatinating ?Any suggestions on acheiving this? any help is greatly appreciated.
miro

How would you arrive at 242576 from 24, 25 and 76 when performing the operation by hand, on paper? What calculations would you need to perform?
Your other requirements are standard properties of programming: unless you go out of your way to make it otherwise, methods/functions tend to produce the same output based on the same input.
BTW, you won't need any math classes for this, just mathematical operators like +, -, *, / etc.

Java.math package does not exist!!!

hi java experts, i really desperately need some help. ihave been trying to compile a java program i have written that imports the java.math package as i am using the BigInteger class. I am using SUN ONE STUDIO ME 4 and have j2se SDk installed. when i try to build the program in the IDE, it gives me an error message saying the java.math package does not exist. i can't understand why. i think it's an IDE problem. i tried mounting the filesystem and i mounted almost a million times in diff ways but it still can't compile. i can't find the directory of the java.math to mount into. anyway i tried to compile it at the command prompt and it can compile but with errors... so i figure that i do have the java.math class on my system just that the IDE jsut can't recognise it. i am at my wits end and gonna go mad if someone doesn't please help me.
adeline from singapore

Cross-posted at http://forum.java.sun.com/thread.jsp?thread=293132&forum=54&message=1155073

Package java.math does not exist!!!

hi java experts, i really desperately need some help. ihave been trying to compile a java program i have written that imports the java.math package as i am using the BigInteger class. I am using SUN ONE STUDIO ME 4 and have j2se SDk installed. when i try to build the program in the IDE, it gives me an error message saying the java.math package does not exist. i can't understand why. i think it's an IDE problem. i tried mounting the filesystem and i mounted almost a million times in diff ways but it still can't compile. i can't find the directory of the java.math to mount into. anyway i tried to compile it at the command prompt and it can compile but with errors... so i figure that i do have the java.math class on my system just that the IDE jsut can't recognise it. i am at my wits end and gonna go mad if someone doesn't please help me.
adeline from singapore

java.math package will be there in jdk_dir\jre\lib\rt.jar. You need to set the classpath variable in your IDE for this jar file. There must be some means to edit the IDE's classpath variable.
i mounted almost a million times in diff ways but it still can't compileIf it takes one minute for each mount then total time you have taken = 10000000 minutes = 166666 hours = 6944 days = 19 years (roughly). Java was not there 19 years ago.
Sudha

Java ME SDK 3.0 Math Class

Using Eclipse and Java ME SDK 3.0
When the Application Descriptor configuration is set to use DefaultCldcPhone1 or other emulators in the Java ME SDK 3.0 many of the Math class methods such as Math.sqrt(double arg0) are not available. However if I change the configuration to use a Nokia emulator all the Math class methods become available.
This issue has just shown up since moving from WTK25 to Java ME SDK 3.0
Note:
Under Eclipse/Preferences/Java ME/Device Management the Configuration of all the emulators from the Java ME SDK 3.0 is listed as CLDC-1.0 whereas the other emulators from Nokia and from the Sun Java Wireless Toolkit 2.5 are listed as CLDC-1.1.

It is related to the configuration of the emulator (CLDC 1.0 or CLDC 1.1)...
If the configuration is CLDC 1.0 all the floating point data types (float, double, Float, Double) will not be available...
If you change the configuration to CLDC1.1 , then all the previous types will be available.
PS: I don't know how to do this in EclipseME

ADF Mobile : Could not find property inputvalue in class java.math.BigDecimal

I tried to add an input text item to the list view like below and received an error message while navigating out of the input text field.
"Could not find property inputvalue in class java.math.BigDecimal".
Can someone show me some pointers about what is wrong with the below code.
JDEV Version : 11.1.2.4
<amx:listView var="row" value="#{bindings.Empdtls.collectionModel}"
                        fetchSize="#{bindings.Empdtls.rangeSize}" styleClass="adfmf-listView-insetList"
                        id="lv1" editMode="true">
            <amx:listItem id="li1">
              <amx:tableLayout width="100%" id="tl1">
                <amx:rowLayout id="rl1">
                  <amx:cellFormat width="10px" id="cf3"/>
                  <amx:cellFormat width="60%" height="43px" id="cf2">
                    <amx:outputText value="#{row.ClassCode}" id="ot3"/>
                  </amx:cellFormat>
                  <amx:cellFormat width="10px" id="cf4"/>
                  <amx:cellFormat width="40%" halign="end" id="cf1">
                    <amx:inputText value="#{row.bindings.Salary.inputValue}" simple="true" id="it41"/>
                  </amx:cellFormat>
                </amx:rowLayout>
              </amx:tableLayout>
            </amx:listItem>
          </amx:listView>

Hi,
#{row.bindings.Salary.inputValue) doesn't access a binding in ADF Mobile. Use #{row.Salary} instead.
Frank

Cast to a literal (ex. "java.math.BigDecimal")

I have an array with 2 columns like:
"java.math.BigDecimal", "2"
"java.lang.String", "Test 01"
"java.math.BigDecimal","120"
"java.math.BigDecimal","148"
"java.lang.String", "Test 02"
Is there way to cast the second string to the correct object type, using the first string.
Something like this:
("java.math.BigDecimal")("2")
("java.lang.String")("Test 01")
thanks in advance,
intovoid

You could do this by reflection for classes which
have a contructor which takes an single string
parameter - which I believe all these classes do.
Lot's of messy expections to field. The sequence
would be something like:
private static Object create(String[] columns) throws
Exception {
Class clazz = Class.forName(columns[0]); // get
the class
Contstructor cons = clazz.getConstructor(new
Class[]{String.class}); // get constructor from
String
return cons.newInstance(new Object[]{columns[1]});
// construct object
code]Except, the problem remains that the OP can still not cast the Object returned by newInstance() by using the String in columns[0] (even though the Object is a BigDecimal). Even if it could be cast "dynamically", what would it be cast into - you can not dynamically declare the variable type.
The above method could work if all the possible objects returned implemented a common interface. Or maybe instanceof could be used to hard-code the cast to the possible objects.
In the end, I think this type of code can lead to a brittle design.

Trig functions in the Math class

One of the techniques suggested to master for the Java Programmer exam is using the trigonometry methods in the Math class. Does that mean that on the exam I would need a trigonometry knowledge or is it enough to be familiar with their signature ?

No trig knowledge - just questions on the Java language, including method signatures. Check out the various mock exams such as at http://www.javaranch.com/certfaq.jsp

@value tag dosen't work for java.math.BigInteger constants

Is there anything I can do to get the Javadoc {@value} tag to document the value of BigInteger constants?
I presume the issue applies to any object constants, but, BigInteger is all I need.
Thanks for any advice.

I apologize, I should have supplied more context....
Here is my sample source
package ...;
import java.math.BigInteger;
public class TestJavaDoc
* TEST_STRING has value {@value}
public static final String TEST_STRING = "IFQ Permit ";
* TEST_BIG_INTEGER has value {@value}
* Should also work like this {@value #TEST_BIG_INTEGER}
* Constant ONE has a value {@value BigInteger#ONE}
public static final BigInteger TEST_BIG_INTEGER = BigInteger.valueOf(1000);
Here is the generated Javadoc, where you can see that @value works for a String, but fails for BigInteger....
TEST_STRING
public static final java.lang.String TEST_STRING
TEST_STRING has value "IFQ Permit "
TEST_BIG_INTEGER
public static final java.math.BigInteger TEST_BIG_INTEGER
TEST_BIG_INTEGER has value {@value}
Should also work like this {@value}
Constant ONE has a value {@value}
Here is more context:
javadoc -J-versionjava version "1.4.2_09"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_09-b05)
Java HotSpot(TM) Client VM (build 1.4.2_09-b05, mixed mode)
excerpt from build.xml:
<target name="larryDoc"
description="Generates JavaDoc Business Rule classes">
<tstamp>
<format property="generation.time" pattern="MM/dd/yyyy hh:mm:ss aa"/>
</tstamp>
<javadoc
destdir="./businessRules"
author = "true"
version = "true"
use = "true"
windowtitle = "Business Rules"
additionalparam="-breakiterator">
<fileset dir="../business/src" defaultexcludes="yes">
<include name="org/psmfc/er/business/TestJavaDoc.java"/>
</fileset>
<classpath>
<path>
<pathelement path="IER/business/classes"/>
</path>
</classpath>
<bottom>generated: ${generation.time}</bottom>
</javadoc>
</target>

I can't use Math.class

I can't use Math.class although I import java.lang.*.
plz help me.

and tell us what you mean by "can't use"My father began to work a PC as he was already
retired. He has been fighting with it ever since.
Sometimes he calls me for help crying "everthying has
disappeared!"
I ask him: "What is 'everything' and what does it
mean 'disappeared'?"you could then go on to throw a further spanner in the works by asking what "has" means :)

Question about Math Class

I have a couple of Java questions I was wondering if anyone could answer:
1). In this one statement, which takes the greatest common denominator and places it in the variable commom:
int common = gcd (Math.abs(numerator), denominator);
A).What is gcd? I looked it up and it's not a reserved word in the math class. In the class that this statement comes from there is no variable, object, or method named gcd. There is also no gcd variable, object, or invoked method in the client code that uses the class that this statement comes from.
B ). I know that abs is a method of the math class for the absolute value of a number(in this case the number inside the variable numerator.). And I know that when the abs method is invoked it sends the variable 'numerator' as the parameter for the data to take the absolute value of. What I don't understand is the syntax of this statement in regards to how you can take the absolute value of the variable 'denominator' haveing a variable 'numerator' inclosed in the parenthesis and simpley adding a comma to include the variable 'denominator' in the argument to be sent in the invocation of the abs method. It seems like this would be the correct syntax:
int common = (Math.abs(numerator))/(Math.abs(denominator));
Can anyone explain the 'int common = gcd (Math.abs(numerator), denominator);'
statement?
Thanks,
-dman

> A).What is gcd?
As already been said: it's the Greatest Common Divider.
Example: fraction 9/24, then gcd(9, 24) == 3.
>It seems like this would be the correct syntax:
int common = (Math.abs(numerator))/(Math.abs(denominator));
Probably the gcd(...) method is used to normalize a fraction whose denominator is always positive. If the fraction is smaller then zero, the numerator is negative. And to caculate the Greatest Common Divider of two numbers, the gcd(...) method needs two positive arguments.
Google for "Euclid GCD algorithm".

Java.math.BigDecimal;

Hello every one thanks for your time . i am trying to understand about decimal method. example below well explain itself but i m trying to use userInput in decimal & then add the result but cant work out. any one like to give me any good example or explain which ever easy way for you guys
Thanks in advance.
import java.math.BigDecimal;
public class AddTwoBigNumbers{
public static void main(String[] args) {
    BigDecimal num1, num2;
    num1 = new BigDecimal(50.020);      "      50.020 is fix value here. How i can change with user input method. "
    num2 = new BigDecimal(100.50);
    Sum(num1, num2);
public static void Sum(BigDecimal val1, BigDecimal val2){
    BigDecimal sum = val1.add(val2);
    System.out.println("Sum of two BigDecimal numbers: "+ sum);
}

Another nice hint might be: you actually can use this args array thingy up there. Start your program like
java AddTwoBigNumbers 50.02 100.50and access both values via args[0] and args[1] respectively.

Using java.math

Hey guys,
I've got yet another question !
I want to the math.floor to round my double numbers down.
I've declared "import java.math.*;" at the very start
but how do you use math.floot actually?
I've put
double number = 1.25
double roundednumber = math.floor(number);
but it cannot find symbol math...I did something wrrong...

Hey guys,
I've got yet another question !
I want to the math.floor to round my double numbers down.
I've declared "import java.math.*;" at the very start
but how do you use math.floot actually?
I've put
double number = 1.25
double roundednumber = math.floor(number);
but it cannot find symbol math...I did something
wrrong...As Jos already pointed out: it's with a capital M.
Note that the Math class is not in the java.math package but in the java.lang package which is automatically imported.
This is the java.math package:
http://java.sun.com/j2se/1.5.0/docs/api/java/math/package-summary.html
And this is the java.lang.Math class:
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Math.html

Pow() method from java.math

Hi,
Can any body explain to me how can I use this method. In pow(int exponent) can I pass a plain int as argument. So if want 2 ^3 than I just pass 3 as an argument.
Can I do this to get the same result?
x = 2;
x.pow(3);
Does anybody have a good example that I can look at?
Any help would be great!
Thanks,
moni

Here's a complete example:
import java.lang.Math.*;
import cs1.Keyboard;
public class Power {
     public static void main (String[] args) {
          double a, b;
               System.out.print("Enter a value: ");
               a = Keyboard.readInt();
               System.out.print("Enter the power you would like " + a +
                    " raised to: ");
               b = Keyboard.readInt();
               double answer = Math.pow(a,b);     //call to the function pow() of
                                                       //the Math class
               System.out.println(a + " raised to the power of " + b +
                    " equals: " + answer);
}

Java Math Class

Similar Messages

Maybe you are looking for