Compute Standard Deviation For A Set Of Numbers - ClassCastException Being Thrown?
Apr 20, 2015
Basically I'm trying to compute the standard deviation for a set of numbers and I'm using previously know data to compute this. The data I'm working with is here (note all of this is fake as its for an assignment):
Next this is the code that I know is producing the error:
/**
* Pass in original data from files, and pass in computed grades as arraylist. this returns all of the standard deviations to be printed
*/
public static ArrayList calcStandDev(String data1[], ArrayList<Double> grades, ArrayList<Integer> averages)
{
double standDev = 0;
int j = 0;
//gets rid of first element in string array, makes processing MUCH easier
String[] data = Arrays.copyOfRange(data1, 1, data1.length);
[Code] ....
Look for the line with all the ***'s, it is producing the "java.lang.ClassCastException: java.lang.Double cannot be cast to java.lang.Integer".
The reason I dont undersand why its producing this error is because temp.get(i) should be a integer - averages.get(i) (is type double), I do believe automatic up casting is present here making them both a double then I multiply it by itself producing a double? I dont understand where the casing is occurring. And just incase you want the formula I'm using for standard deviation here it is:
The purpose of this program is to import via keyboard Numbers.txt and calculate the mean and standard deviation to Results.txt.I am able to get the mean calculate but when I open the Results.txt the standard deviation is 0. I don't know what is wrong with my code, but I believe it has something to do with the scanner being close. Here is the error message i receive after inputting Numbers.txt.
java.lang.IllegalStateException: Scanner closed at java.util.Scanner.ensureOpen(Unknown Source) at java.util.Scanner.hasNext(Unknown Source) at StatsDemo.main(StatsDemo.java:48) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)
Java Code:
import java.text.DecimalFormat; //for number formatting import java.util.Scanner; //for keyboard input import java.io.*; //for using files public class StatsDemo { public static void main(String [] args) throws IOException
for standard deviation my output is not rounded to the 10's place, how can I make it round to the 10's place. Here is my code.
import java.util.*; public class chapter7 { public static final int Max_Number_Scores = 100; public static int fillArray(double[] scores) { System.out.print("You entered "); for (int i = 0; i < scores.length; i++) { System.out.print(scores[i] + " ");
It may be (it is highly likely) possible that I have royally stuffed this up. I am attempting to write a program that asks a user for a file name, gets the number of entries and if there is more than one entry calculate the mean, variance and standard deviation. This is my code so far:
/* Calculate contains methods that determines the number of data entries in a file, and calculates the mean, variance and standard deviation of this set * ************************************************************************/ import java.util.Scanner; import java.io.*; public class Calculate { public static void main(String[] args) throws IOException { // Create a Scanner object for keyboard input. Scanner keyboard = new Scanner(System.in);
[Code] ....
The errors I am getting are:
Calculate.java:67: error: ';' expected mean += mean/String filename; ^ Calculate.java:67: error: not a statement mean += mean/String filename;
I am trying to create a method that calculates the standard deviation of array. What I want to be able to do is something like this
package standardDevaitionAndMean; public class StandardDeviationTest { public static void main (String[] args) { int [] array = {12,12,12,12,12,12,12}; standardDev = array.StandardDevation(); System.out.print(standardDev); } }
With something like this
package standardDevaitionAndMean; public class StandardDeviation {double mean1; double standDev; public double Mean(double ... array) { for(int i=0; i<array.length;i++)
[Code]...
So basically I want to be able to make an array in a class and be able to calculate its standard deviation with my method in my other class. I know the code I wrote is terrible but I just wanted to show what I am trying to do. I am kind of shaky on how arrays operate
My verify method also always returns false. So I'm given three classes to begin with. Calculator, Expression, and InfixExpression and they are listed below.
The goal is to create a class called PostfixExpression that extends Expression and can read and calculate postfix expressions.
My evaluate() method works for most calculations but when it needs to return a negative value it just returns the positive equivalent.
Also, my verify method always returns false and I can't pinpoint why.
Here's my current code. Some things are commented out for debugging purposes.
import java.util.Scanner; /** * Simple calculator that reads infix expressions and evaluates them. */ public class Calculator { public static void main(String[] args) { Scanner input = new Scanner(System.in);
I'm doing a project in netbeans. I have to make a on-line bank with all the GUI. In the middle i got stuck with the classcastexception..
public class Banca { public static void main(String[] args) throws IOException, ClassNotFoundException { // dati dei clienti Anagrafica c = new Anagrafica();
[code]...
And here's the class of the activities of an account.. I'm not posting my classes Conto( Bankaccount) & Movimento (Activity) because those two already do what they should..
throw new RecordNotFoundException("E888", "This is custom message X"); }
My questions are:
Is this the correct way to invoke a jsp when my code throws an exception?Do I need a try catch block to handle the thrown RecordNot Found Exception, if yes how would I navigate to the jsp from the catch block?
I have been working with socket programming. I was trying to develop a two way communication from server to client. The data is being received when sent from server to client but there is a problem when I am sending from client to server.
I am getting an error as "Socket is closed" pointing to the line where I have created a BufferedReader. I have simplified some part of my code to be very specific.
Code attached.
import java.io.*; import java.net.*; import java.util.*; public class Server { public static void main(String args[]) { String id="policeone"; int hashcodeid=0;
[Code] ....
Error::
Receiving string from client: 'java.net.SocketException: Socket is closed at java.net.Socket.getInputStream(Socket.java:872) at Server.main(Server.java:51)
Below is a code of a simple file downloader in java. I want to detect an exception when the connection is broken in the middle of downloading a file. Now, I run the code and in the middle of downloading the file, i turn off my wifi with keyboard wifi off button. Doing this the program hangs forever without throwing any exceptions and without terminating. It seems it blocks forever.why is exception not thrown? Secondly, in the following code you can see this line //con.setReadTimeout(2000); which is currently commented out. Removing the comment and running the program, now if connection breaks in the middle by turning off wifi then it waits for 2 seconds and then if it cannot read then it terminates without throwing exception. So, again in this case why is it just terminating and not throwing any exception?
I am getting the above error and am not sure which direction to proceed. In the class, the only way we have discussed getting user input is by System.in.read. I have searched and apparently found better methods for getting user input, but wanted to stick with what has been presented thus far.
Assignment Directions:
1. Create a new class named “valuemethod”
2. Create a new method named “Main”
3. In Main Write the code that will call the method EnterPay and YearlySal
4. Create a new method named “EnterPay”
5. In the EnterPay method Write the code that asks the user to input their hourly wage. Use the formula to calculate their yearly salary: wage * 2040. Return the yearly salary to the main method
6. In the main method write the code that will display this: “Your yearly salary is:
Java Code:
package valuemethod; public class Valuemethod { public static void main(String[] args) //throws java.io.IOException -- moved to EnterPay
I just wanna confirm that when a certain processing throws an exception even when said exception happens inside doFilter, any servlet container will never proceed to the next filter right?
I am attempting to create a very simple game where two squares move around and each can see the other square moving. This is a multi-player game over a TCP network using JavaFX. I am getting an illegal state exception when I call requestFocus(). This is my server:
public class GameServer extends Application { ObjectOutputStream p1out; ObjectOutputStream p2out; int PLAYER1 = 1; int PLAYER2 = 2;
Allow the user to specify the number of terms (5 terms are shown) to use in the computation. Each time around the loop only one extra term should be added to the estimate for PI.
Alter your solution from part one so that the user is allowed to specify the precision required between 1 and 8 digits (i.e. the number of digits which are correct; e.g. to 5 digits PI is 3.14159), rather than the number of terms. The condition on the loop should be altered so that it continues until the required precision is obtained. Note that you need only submit this second version of the program (assuming you have it working).
My output for part 1 is :
Enter number of wanted terms for value of PI 100 PI = 3.1666666666666665 Number of Term = 2 PI = 3.1333333333333333 Number of Term = 3 PI = 3.145238095238095 Number of Term = 4 PI = 3.1396825396825396 Number of Term = 5 PI = 3.1427128427128426 Number of Term = 6 PI = 3.1408813408813407 Number of Term = 7 PI = 3.142071817071817 Number of Term = 8 PI = 3.1412548236077646 Number of Term = 9 PI = 3.141839618929402 Number of Term = 10 ................ and so on
I know you have to compare value of current Pi to the previous one but I'm stuck.
I need to create a simply application that would display the results of two dice thrown five times and the total of those results. This is shown below in the attached file.
The problem is, I have a do-while loop that loops 6 times. Inside the loop, I have 2 random.nextInt(5) that generate random numbers. But how can I output the total? How can I make a variable equal to the sum of the two random numbers if the two random numbers are located inside a do-while loop?
Attached below is also the code I have thus far.
(Attached below is both files: what it needs to look like, and what it currently looks like)
I have to write sorting algorithm for numbers given on standard input(console) with following requirements:
The application must remember the distinction between double and integer numbers. This must be evident in the sorted output. Double type numbers are written using a period (.) to separate the fraction from the whole part.
The problem is I don't know how to efficiently distinct whether something is an int or double on standard input, to save them into 2 different arrays.
Only idea I've come to so far is to read each number as String and check if it has '.' character, to figure out if it's double and than convert it into right type and add it to correct array.
Also thought that maybe this would be achieveable using Pattern but how to do that?
This is what I have so far, but I don't know how to continue:
import java.util.Scanner; public class ArithmeticComputation{ public static void main(String[] args) { Scanner stdin = new Scanner(System.in); int num1 = stdin.nextInt();
[Code] ....
I'm looking for a method that allows me to assign char into actual operators, so that I can loop through all the computation.
In my cs class, we have to write a program that throws an exception if the user enters a negative number, the program should prompt the user to enter only positive numbers and then let them retype the number. But everytime I throw an exception, my program gets suspended.
What am I doing wrong, or is there no way to continue a program if an exception is thrown? Does the program automatically get suspended when an exception is thrown?
try{ do { N = kb.nextDouble(); if(N<0) { throw new NegativeArraySizeException(); } else j++; } while(j==0); fill.size(N); } catch(NegativeArraySizeException e) { System.out.println("The number you entered must be positive. Please try again."); }
This is what I need to do: Write a method called scientific that accepts two real numbers as parameters for a base and an exponent and computes the base times 10 to the exponent, as seen in scientific notation. For example, the call of scientific(6.23, 5.0) would return 623000.0 and the call of scientific(1.9, -2.0) would return 0.019.
This is the method I have written:
public double scientific(double num1, double num2); { double base = num1; double exp = num2; double scientific = base * Math.pow(10, exp); System.out.println(scientific); return scientific; }
These are the following error messages I received when trying to compile the code:
Line 4 missing method body, or declare abstract missing method body, or declare abstract public double scientific(double num1, double num2);
<import javax.swing.JOptionPane; public class TempCalc {
public static void main(String[] args) {
//Confirming which conversion to compute. String FarOrCel = (JOptionPane.showInputDialog("Would you like to calculate a Farenheit value or a Celsius value? (Enter Farenheit or Celsius)");
[Code] ....
So I've been trying to come up with a Farenheit to Celsius converter and back. However, whenever I run the program in JCreator it never recognizes the string "Farenheit". Even if I put that exact thing (I copy/pasted from the if (FarOrCel == "Farenheit")) it keeps asking me for a Celsius value.
[quote name='INNOCENTREAPER##!' date='28 September 2014 - 07:40 PM' timestamp='1411958437' post='2057072']
<import javax.swing.JOptionPane; public class TempCalc { public static void main(String[] args) {
//Confirming which conversion to compute. String FarOrCel = JOptionPane.showInputDialog("Would you like to calculate a Farenheit value or a Celsius value? (Enter Farenheit or Celsius)";
I was wondering how Java knows where to Import classes from when we don't specify the whole directory path.
For example: import java.util.* Does It automatically search In both your current directory and the directory created during Installation that contains the standard library (wherever It may have been Installed) ?
I am facing NoClassDefFoundError with one of the java standard platform class (java.text.DigitList$1)
java.text.DigitList class is part of rt.jar so it should not create any issue as such.
I am using Java 1.6.0_06
StackTrace: Unhandled exception java.lang.NoClassDefFoundError: java/text/DigitList$1 at java.text.DigitList.shouldRoundUp(DigitList.java:4 11) at java.text.DigitList.round(DigitList.java:363) at java.text.DigitList.set(DigitList.java:351) at java.text.DigitList.set(DigitList.java:272) at java.text.DecimalFormat.format(DecimalFormat.java: 584) at java.text.DecimalFormat.format(DecimalFormat.java: 507) at java.text.NumberFormat.format(NumberFormat.java:26 9)
Write a program that computes the cost of painting and installing carpet in a room. Assume that the room has one door, two windows, and one bookshelf. Your program must do the following:a. Prompts the user to enter, in feet, the length, width, and height of a room.
A. Read the dimensions of the room.
b. Prompts the user to enter the width and heights, in feet, of the door, each window, and the bookshelf. Read these quantities.
c. Prompts the user to enter the cost, per square foot, of painting the walls. Read these quantities.
d. Prompts the user to enter of cost, per square foot, of installing carpet. Read these quantities.
e. Output the cost of painting the walls and installing the carpet.
