Using TXT File As Array
Sep 1, 2014
So I have to take a text file with a bunch of scores and store it into an array, sort it in order and in rows of four, then create methods to get the highest score, lowest, average, median, etc. I've been working on this for about two days and anytime I read something I just confuse myself further. I want to get this assignment done, but at the same time I want to understand how it works. This is what I have so far and I'm getting a NullPointerException error. Obviously I haven't filled out some of the methods because the problem is the main:
package arrayops1d;
import java.io.*;
import java.util.*;
public class ArrayOps1D {
static int scores[];
public static void main(String[] args) throws Exception{
FileReader file = new FileReader("C:/Users/Steve/Documents/"
+ "NetBeansProjects/ArrayOps1D/Scores.txt");
BufferedReader reader = new BufferedReader(file);
[code]....
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Mar 24, 2015
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];
[Code] ....
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Dec 8, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code] .....
And then here is the data from the text file that i must extract to use to create product objects.
Dill Seed,938,34
Mustard Seed,100,64
Coriander Powder,924,18
Turmeric,836,80
Cinnamon (Ground Korintje),951,10
Cinnamon (Ground) Xtra Hi Oil (2x),614,31
Cinnamon (Ground) High Oil (1X),682,19
These continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quantity after the second comma.....
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Dec 9, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data. Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code]...
these continue for about 40-50 entries, they are not seperated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name seperated with spaces, then price after a comma, then quanity after the second comma.....
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Dec 8, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
//Constructor
public Product( String pName, double price, int quanity )
[code]....
and then here is the data from the text file that i must extract to use to create product objects.
Dill Seed,938,34
Mustard Seed,100,64
Coriander Powder,924,18
Turmeric,836,80
Cinnamon (Ground Korintje),951,10
Cinnamon (Ground) Xtra Hi Oil (2x),614,31
Cinnamon (Ground) High Oil (1X),682,19
these continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quanity after the second comma.....
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Jul 14, 2014
New to programming. Am supposed to create a program that reads a text file (of integers) and computes a series of computations on these integers. I don't have the code for the integers in my code yet, (i know how to do those), but am struggling getting the array to simply print in the print writer. I have the user select a text file, read the file with a scanner, and then save the computations done from my code into another file. specifically, the problem is as follows: Write a program that uses a file chooser dialog to select a file containing some integers. The file contains an integer N followed by N integers. The program then uses a file chooser dialog to let the user specify the name and location of an output file to write results to.The data written to the output file will be as follows
(1) The original list of N numbers from the input file,
(2) The original list of N numbers printed in reverse order of how they appear
in the input file.
(3) The sum and average of these numbers,
(4) The minimum of all the numbers,
(5) The maximum of all the numbers.
[import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;
[Code]....
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Mar 21, 2015
I am trying to read a file and input each line of the file into an array. I have not set the array size as I was hoping to fill the array using a while loop. Unfortunately the scope of the array does to work inside the while loop so I am being told that the array 'students' has not been initialised even though it has just outside of the while loop. Is it possible to do what I am trying to without having the array initialised in the while loop as surely the array will be reset every time if it was in the while loop? Here is my code:
public static void students(String file) throws FileNotFoundException {
try {
File studentInfo = new File(file);
Scanner input = new Scanner(studentInfo);
String[] students;
[Code] ....
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May 17, 2015
My assignment is to encrypt and then decrypt a file in Java. I used an array to add 100 to each character per the assignment but I need figuring out a way to subtract the 100 from each character so the file is decrypted again. I tried to create another array to decrement the 100 from each character but cant seem to figure it out/get it working. Here is my assignment and my code so far:
"Although there are complex encryption techniques, you should come up with a simple one of your own. For example, you can read the first file one character at a time, and add 100 to the character code of each character before it is written to the second file.
Then write a program to decrypt the second file. The program should read the content of the second file, restore the data to its original state, and write to a third file."
import java.io.*;
public class FileEncryption {
public static void main(String [] args)
throws IOException {
int[] encrypt = { 100 };
[Code] ....
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Jun 4, 2014
There is a csv file that contain 10 rows and two columns. I want to convert this csv file to array. Each cell contains several line of string. But the output is wrong. After printing output, each cell of array contains a line of one cell of csv file.
for example csv file contain
book, this book is good. that book is good.
cook, cooking is enjoyable.
After printing output of array:
book,this one is good
that book is good, null
what is wrong with this code?
Code is :
public static void main(String[] args) throws Exception {
Scanner main = new Scanner(new File("C:UsersaDesktopook1.csv"));
int line=0;
String [][] temp1=new String [10][2];
while (main.hasNext()) {
temp1[line]=main.nextLine().split(",");
line++;
}
}
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Sep 25, 2014
I have a file called statecapitals.txt that is read in, I want to store it in either a 2d array or hashmap and select a random state then Ask the user for the name of the capital. Then I want to Let them know if they are correct or not and have a choice to play as many times as they like. When they no longer want to play,I want to let them know how many they got correct and how many incorrect. I am not sure which would be better a hash map or 2d array and dont know where to start with each.
here is what the text file looks like:
Alabama - Montgomery
Alaska - Juneau
Arizona - Phoenix
Arkansas - Little Rock
California - Sacramento
Colorado - Denver
[code]....
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Apr 19, 2014
I am working on a project and for one step, I need to load an array (which in this case, students[]), with the records in another file.
So, should I used the try, catch method?? I am just not sure about the array. I know how to read from a file, but, I didn't get the idea of loading an array.
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Apr 20, 2014
I am trying to write a Float Array to a file but it is only writing the last line of the array to a file. I have also attached the entire assignment as a zip file with all required files. Here is the part of the code I am having issues with:
Java Code:
for (int i = 0; i < differenceArray.length; i++){
System.out.println ("Date: "+ dateArray[i] + " Opening: " + dataArray[i][2] + " Closing: "+ dataArray[i][5] + " Difference: " + differenceArray[i]);
try(FileWriter writer = new FileWriter("C: emp" + fileName + ".txt")){
writer.write(Float.toString(differenceArray[i]));
[Code] .....
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Jul 13, 2014
I'm new to java and I'm trying to figure out how to read a file like this:
Jan26081.5910211.79
Feb23301.5918221.79
Mar24261.5922101.79
Apr23751.6921431.79
May24001.6915381.79
And output the file and print it into an array with total under it.
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Nov 17, 2014
I have to write a program for sorting an array of random numbers by the users choice. These random numbers are stored in a text file, which the user inputs, and is then stored into an array for sorting. I won't have a problem with the sorting algorithms, but I've never had to read a text file and store it into an array before
The text file has the numbers stored like so :
148
626
817
4
312
652
643
etc....
I gather that I'll probably have to user the Scanner for the user to input the text file name, but how do I store it to an array? So far I only have the bones of the program done, like so
import java.util.Scanner;
public class SortingAlgorithms {
public static void main(String[] args) {
[Code].....
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Mar 22, 2015
How do I read in a file line by line into an array without using arraylist?
I know how to do this using BufferedReader, but I am wondering how to do this using Scanner? When I used BufferedReader I noticed that there must be two exceptions to be caught which were IOException and FileNotFoundException, whereas a Scanner needs only a FileNotFoundException, why is that?
Java Code: public class practice {
public String[] array;
Scanner inputStream = null;
Scanner n = new Scanner(System.in);
public String line;
[Code].....
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May 5, 2015
I'm currently working on a program what is reading a txt file with a bunch of numbers in it but keep getting an error back.
Validator.java:
import java.io.IOException;
import java.io.File;
import java.util.Scanner;
public class Validator {
public int[] accounts = {};
[Code] ....
Accounts.txt:
5658845
8080152
1005231
4520125
4562555
6545231
7895122
5552012
3852085
8777541
5050552
7576651
8451277
7825877
7881200
1302850
1250255
4581002
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Oct 25, 2014
I am trying to read in lines of text from a file then prints out the text. I only need one 2D array and can't copy from one array to another.This how the file looks like:
4 4
FILE
WITH
SOME
INFO
I have been able to read the file but when I am trying to run my program I have blank spacing instead of an array.
import java.util.Scanner;
import java.io.*;
public class Array {
public static void main(String[] args) throws IOException{
[code]....
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Jun 5, 2014
I can read the data to a monitor perfectly. But, I'm having problem reading data from an external file into an array of class objects. Here's my attempt at writing the method:
private void openFile()
//This method asks the user to enter a file name(including the file extension) and then
//Sets the data to an array of Product type {
String fileName, storeName="", emptyLine1="", emptyLine2="", name="", productName="";
int demandRate=0;
double setupCost=0.0, unitCost=0.0, inventoryCost=0, sellingPrice=0;
Scanner inputStream = null;
[code]...
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Feb 23, 2014
I am trying to make a class definition file for an ASCII File.
Ultimately, I want to be able to add methods to allow the image produced by the file to be printed normally, then printed with various manipulations.
However, for some reason, whenever I try to run the program to test my normalPrint method, it terminates without printing anything.
I think this is because the array's values width and height are not within the scope of the method. I tried passing the array as a parameter for the method like so:
Java Code:
public void normalPrint(char [][] poop){
//method here
} mh_sh_highlight_all('java');
But it gave me an error that stated
"The method normalPrint(char[][]) in the type asciiFile is not applicable for the arguments ()"
Class Definition:
Java Code:
import java.io.*;
import java.util.Scanner;
public class asciiFile {
int height;
int width;
[Code] .....
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Apr 10, 2015
Every time i try and add a new word to personalDictionary, it only replaces the first index. In my personalAdd method i had tried to add a running count to advance the position it would be saving in but it doesn't seem to be working correctly...
Java Code:
import java.util.Arrays;
import java.util.Scanner;
import java.io.File;
import java.io.PrintWriter;
import java.io.FileNotFoundException;
public class SpellingChecker
[Code] ....
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May 26, 2014
I have a simple txt file, each line simply containing 1 word.I would like each work to represent an index of the array..im having some difficulty populating an array from either a txt file or a scanner.i seem to be able to fill the scanner so to speak with the contents of the text file but not the array. I don't know how to syntax it
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.Arrays;
public class ReadFile
public static void main(String[] args) {
[code]....
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Oct 11, 2014
I have a program I am trying to get together for class. Its a simple calendar, and I'm trying to save an array of dates to a file to be able to recall at will. I have done a fair amount of research but couldn't find a solid method to what I'm trying to do. I have a method that will check the inputted date's file to retrieve or save an entry. Here is where I'm stuck.
baseFile = new File("C:\Users\Ian\Documents\Eclipse (Java)");
private void getFile(String month, String year) throws IOException {
String filename = new String(baseFile+"\"+month+year);
File file = new File(filename);
if(file.exists()){
[Code] ....
This is pretty much the most reasonable method I could find. this is called as a sort of plug for two other methods to call. Everything compiles, no errors or warnings, but no files are being created.
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Apr 15, 2014
I am reading records from a txt file and storing it into an array
import java.util.*;
import java.io.*;
public class PatientExercise {
//patients exercise time
public static void main (String[]args) throws IOException{
Scanner in = new Scanner(new FileReader("values.txt"));
double [] patientTimeRecords = new double [300];
int noExerciseCount=0, numPatients =0;
double highest=0, lowest=0, avg=0, totalTime=0;
[Code] ....
However an error msg keeps popping up:
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:907)
at java.util.Scanner.next(Scanner.java:1530)
at java.util.Scanner.nextDouble(Scanner.java:2456)
at pastpapers.PatientExercise.main(PatientExercise.ja va:44)
line 44 is:patientTimeRecords[i]= in.nextDouble();
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Feb 19, 2015
Working on a program that creates an array from a file, organizes it in various ways, and then prints the results. Right now I'm specifically having trouble with the printAry() method - when I try to run it, I receive a NullPointerException for the active line in printAry() (EDIT: line 102). Not sure which sections are important to this, so I will include the client class and most of the service. I realize that the amount of documentation I included is not necessary, but it is required for the class.
class Lab3StudentAryService
{
private int count;
private Lab3StudentData [] studentAry = new Lab3StudentData[50];
/*
@param: none
@return: none
reads file and converts to array.
*/
public void fillAry() //constructor
{
Scanner scan = new Scanner(System.in);
[code]....
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Apr 30, 2014
i have I byte array ,That I was getting from the gps packets , I need to convert that into jpg file
public static void writejpegfile(byte[] someByteArray) throws FileNotFoundException, IOException {
FileOutputStream fos = new FileOutputStream("image" + new Date().getTime() + ".jpg")
try {
[Code]....
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Mar 19, 2015
I was wondering if it's possible to do this: I want to build a java program that reads a java array from a text file.
Then I want to read it, and output it in a different format.
The reading and out is easy - as text.
But how can I incorporate the read text in to a java valid array in my program, which I can use?
Is this even possible?
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