Unable To Create Method That Calculates Standard Deviation Of Array
Jun 15, 2014
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
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;
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
I have a question about an error I am getting when trying to pass a two dimensional array to a method. I keep getting the "incompatible types, int cannot be converted to int[][]". I am getting the error in a few different place (see comments - at the first call of the method, at a recursive call, and at the return statement. I believe I am passing the same type of array in all cases to the type of array defined in the method parameters.
Below is my code.
// this is a call from the main method int[][] c = new int[temp1.length][temp1.length]; c = MatrixMultiply(a,b); // this is first place the error occurs } // end main public static int MatrixMultiply(int[][] A, int[][] B) { // throw new UnsupportedOperationException("Not supported yet."); int a[][] = A;
I need to create a method that returns a new array containing the componentwise sum of its arguments(if length is the same). For instance, if the input arrays are {0,1, 2} and {2, 2, 3} then the output is {0+2, 1+2, 2+3}, i.e. {2,3,5}.If the input arrays have different numbers of elements, the method should return null.
I came with something like this, however i dont know how to make a copy of an array from two arrays. My code obviously wont compile. package whatever;
import java.util.Arrays; public class hhhh { public static void main(String[] args) { double [] a = {1,2,3}; double [] b = {2,3,4};
so i have this question where it wants me to create a recursion method that takes ONLY THE ARRAY as a parameter, and without using loops or static variables inside the method, and then the method returns the smallest value in that array. However, i tried making the simple if statements where i compare the first element of the array with the second element using the length of the array and decreasing it to get the next elements and compare it again by calling the recursion method, but the problem is when i call the method again, the length does not decrease, even if i store it in a variable, the variable will initialize itself again, and the length wont change.
I am trying to create an MP3 player with a totally customized look and feel to it. I know how to do this with .net, but I must be missing something in Java.
I want to be able to NOT have to present the user with the default mediaPlayer.getControlPanelComponent() in order to control the media player. I want to be able to code it to when the user clicks on my "Play" button, I can tell the player to play the song, and so on.
i have a problem in connecting my jsp program in MSsql 2005 i want to create a connection in my jsp program to MSsql database but theres an error of my work here is my code
I am trying to create a program for class the uses two dimensional arrays. I am stuck on the second step that states Use two parallel arrays. One is a two-dimensional array -- a row of this array will hold six values in this order: [0] number of hours worked, [1] hourly pay rate, [2] gross pay, [3] net pay, [4] federal withholding, and [5] state withholding.
This is what I have so far:
Java Code:
double [][] data = new double [30][6]; String [] names = new String [30]; String str = null; String detail = null; int n = input(data, names, inputFile); mh_sh_highlight_all('java'); (there's more but i don't believe it pertains to this question)
My question is how would I create this array. Or, is that right above? I've searched online and in my book and I just don't understand.
I am trying to create a serversocket that send a binary in parts ie send 1024 bytes then wait for acknowledgement from the client before sending the next 1024. I am able to do it in udp but the client is tcp. This is my code so far
import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.ServerSocket; import java.net.Socket; public class TestFtp {
[Code]....
I have not been able to send then receive acknowledgement before sending the next 1024 bytes.
I am completing a USACO online problem and am trying to create a print writer to write to my file(ride.out). I did this:
PrintWriter out = new PrintWriter(new BufferedReader(new FileWriter("ride.out")));
However, a load of undefined constructor errors come up for PrintWriter(BufferedWriter) and BufferedWriter(FileWriter). I have imported java.io.* so I don't know what the issue is. This has worked before.
I need to debug the equals method implementation of a class I've made, but I cannot for the life of me get Netbeans' debugger to step into it. I can step into other methods from the class (most of which implement the methods in an interface) that are called in the main method (just like the equals method). I've tried...
-Disabling all the step filters -Clearing the Netbeans cache -Moving the call to the equals method out of the if statement it's in and just calling it as its own statement -placing breakpoints within the equals method as well as on the call to the method -placing a method breakpoint on the overridden equals method in addition to the other locations -Using the shift-F7 version of the step into command
I'm using Netbeans 8.0.1 (I don't know if this is the latest version, but the last time I tried to update everything died and I had to completely remove NB and reinstall it) and JDK 8u05 (I think).
I am taking the Class Algorithms and Datastructures and got an assignment for Lab that really throws me off. The goal is to create an Array out of a given CSV file, implement several Methods that get the size of array, etc.
I am still stuck in the first part where the CSV has to be imported into the Array. My problem is that I need a mechanism that figures out the needed size for the Array, creates the array, and only then transfers the data from the CSV.
The list consists of the following wifi related values:
MAC-Adress, SSID, Timestamp, Signalstrength.
These are on the list, separated by comma. The Columns are each of these, and the rows are the four types of values making up the information on a certain wifi network.
The catch is, we are not allowed to use any of the following:
java.util.ArrayList java.util.Arrays and any class out of java.util.Collection.
So far I used the BufferedReader to read in the file and tried to implement the array, but I get an arrayindexoutofboundsexception.
Below is my Code (Its still an active construction zone):
public class WhatsThere { public WhatsThere(String wifiscan) throws IOException { } public static void main(String[] args) throws IOException { // WhatsThere Liste = new WhatsThere(String wifiscan); String[][] arrayListe = new String[0][0];
i am trying to print out a randomly generated array, but i only get
[I@7852e922
i did some research and the "[" is for arrays, "I" is for the int and "@" is the hash. and the rest is some sort of hex. I need to override this in a way, but i can't seem to find out how. this is my current code:
import java.util.Random;
public class Oppgave { public static void main(String[] args){ int myint[] = fyll(); System.out.println(myint); } public static int[] fyll() {
I have a problem where i have to write some code to read through an int array and print out the different integers and how many times they occur. For example:
if the array contained the numbers 1,4,2,3,5,4,4,7,5,4,3,6,8,6,4,
i would need the print to appear something like this
as the array is read sequentialy from element 0 to the end. the program should find the integer value in the first element (increment a counter by 1) and then search all other elements to see if the integer reoccurs (counter++ for each time it reappears). obviously the counter would be the 'times' value in the second column.
My problem is i can get this accomplished yet i cant get the program to recognise when it has already registered an integer in a previous element and skip to the next element looking for a new integer. SO for each element in the array it prints the integer and then searches the entire array for the integer again and increments the counter accordingly. so in essence there is a line printed for each integer the number of times it actually occurs.
I simply wish to have my code to find an integer and the number of times it occurs. and then disregard the elements it has registered the previous integer in.
Also, keep in mind that i am NOT permitted to use any new data structures/arrays for storing/remembering values. I can only use int and double variables throughout.
what i have so far is this: with the array being customerID[] :
Java Code:
int num; int counter; for(int count = 0; count < customerID.length; count++) { counter = 0; num = customerID[count]; for(int count2 = 0; count2 < customerID.length; count2++)
[Code]...
The output for the int array 1,1,3,0,3,2,0,4,1,3, looks something like this:
and as you can see lines are repeated for each time the same integer occurs in a new element. i just need my code to skip an element if the integer has been previously encounterd and recorded. i.e i need it to look more like this :
with the first encountered integer being checked throughout the array and then moving to the next integer/element which is not the same as any previous.
I have been trying to implement custom request method in HTTP header while posting my data to the server URL. My application specific URL accepts -X parameter and -d for the data and it is mandatory for that url. Basically I am trying to dump JSON data into my influx DB using CURL command which is working fine from the shell. But the issue is, if I am implementing the same in java with proper approach, it is not supported or working. My CURL command is :
curl -X POST -d '<my_json_data>' '<my_url>'
How can I implement the same in java using HttpUrlConnection or other available approach?
package timerApp; import java.util.Scanner; import java.util.Timer; import java.util.TimerTask; import sun.audio.*; import java.io.*; public class timerDriver { static int interval;
[Code]...
So I'm trying to make a program that plays an mp3 file after a timer reaches 0, but i keep receiving the error "could not create audio stream from input stream" the audio file is 3.44 MB and 00:03:45 minutes long if that's a problem
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?
I succeed but with limit. the code is below. I cant use advanced material (really just the basics even without loops)
if statements are allowed, and i must use Final variables for key value.
I must use one class and one method (the main}|). I need to prompt the user for a entrance time and exit time, it must be with a space , like 18 00 and not 18:00
Also, if the entrance time is greater or equal to 18 00 the charge is always 20 dollars. If the user enters wrong data or out of range data an output of "ERROR WRONG DATA" and then the programs terminates. Same for wrong time . like if the enter hour is bigger than the exit hour an output of "ERROR entrance time must preccede exit"
for the first hour the output is "no charge", for the second hour the charge is 10 dollars. from the 3 hour for every 15 minutes an additional fee of 3 dollars.
for example if the user entered 10 00 and 13 20 , it should be 52 dollars
** it works for me but if the difference between the entered and exit hours is more then 3 it doesnt work. I could've added another if statements for the bigger hours but it will be very long.
I managed everything. except the last part. That calculates additional 3 dollar for each 15 minutes. what is did is.
converted everything to minutes.
subtract enter time from exit time.
and divide by 15.
thats give me the number of 15 minute periods.
if it last or equal to 4. no charge
else last or equal to 8 . 10 dollars
else...... here is the hard part.
if the total minutes wont divide even by 15 it wont work.
