We Keep Coding

File copier is printing out my whole excerpt, I want it to do it line by line with user input between

I need my program to print this file line by line, waiting for the user to press enter between each one. My code keeps printing the whole excerpt. What do I need to change?
import java.io.*;
import java.util.*;
public class NoteCopier {
public static void main(String[] args) throws IOException {
System.out.println("Hello! I copy an excerpt to the screen line for line"
+ " just press enter when you want a new line!");
try {
File file = new File("excerpt.txt");
FileInputStream fis = new FileInputStream(file);
InputStreamReader inreader = new InputStreamReader(fis);
BufferedReader reader = new BufferedReader(inreader);
String line = reader.readLine();
Scanner scan = new Scanner(System.in);
while(true) {
String scanString = scan.nextLine();
if(line != null) {
if(scanString.isEmpty()){
System.out.println(line);
line = reader.readLine();
}
else {
scanString = null;
break;
}
}
}
}
catch(IOException e) {
e.printStackTrace();
}
}
}

If line is null you'll loop forever; the nested if statements.
I did it in the new Stream style, without the ubiquitous but needless Scanner on System.in.
private void dump(String file) {
Path path = Paths.get(file);
BufferedReader con = new BufferedReader(new InputStreamReader(System.in));
try (Stream<String> in = Files.lines(path, Charset.defaultCharset())) {
AtomicInteger lineCounter = new AtomicInteger();
in.forEach(line -> {
System.out.println(line);
if (lineCounter.get() == 0) {
String input = null;
try {
input = con.readLine();
} catch (IOException e) {
}
if (input == null) {
throw new IndexOutOfBoundsException();
} else if (input.equals(" ")) {
lineCounter.set(10);
}
} else {
lineCounter.decrementAndGet();
}
});
} catch (IndexOutOfBoundsException e) {
System.out.println("< Stopped.");
} catch (IOException e) {
e.printStackTrace();
}
}
With CtrlD you can exit on Windows I believe.
I have added that a line with a Space will dump the next 10 lines.
The ugly thing are the user input lines.
With java.io.Console one can ask input with a String prompt, which then can be used to print the file's line as prompt.
private void dump(String file) {
Path path = Paths.get(file);
Console con = System.console();
try (Stream<String> in = Files.lines(path, Charset.defaultCharset())) {
AtomicInteger lineCounter = new AtomicInteger();
in.forEach(line -> {
if (lineCounter.get() == 0) {
//String input = con.readLine("%s |", line);
String input = new String(con.readPassword("%s", line));
if (input == null) {
throw new IndexOutOfBoundsException();
} else if (input.equals(" ")) {
lineCounter.set(10);
}
} else {
System.out.println(line);
lineCounter.decrementAndGet();
}
});
} catch (IndexOutOfBoundsException e) {
System.out.println("< Stopped.");
} catch (IOException e) {
e.printStackTrace();
}
}
Using a prompt with the file's line, and asking a non-echoed "password" will be sufficient okay. You still need the Enter.
There is one problem: you must run this as real command line. The "console" in the IDE uses System.setIn which will cause a null Console. I simply create a .bat/.sh file. Otherwise System.out.print(line); System.out.flush(); might work on some operating system.

Why I could not save the contents of a file after reading it twice?

Already fixed. Thanks for Mas & ruhul for observing my bugs.
I was trying to read a text file twice, named stationary.txt. The contents of the file has three columns such as the amount, the name of product and the total price.
What I am trying to do first is by averaging each product's price by reading line by line. Then I closed the Buffered and then open it again and read. The second reading takes a variable average and compares each product's price line by line. If line 1 is over the average, then write it into dearer.txt, otherwise write it into cheap.txt
Here is the stationary.txt
1 Highlighter 5.99
2 Pen 9.00
3 Eraser 5.00
4 DrawingPin 2.75
5 Highlighter 10.99
6 FountainPen 20.50
7 Pencil 14.50
Below is the source code
import java.util.*;
import java.io.*;
public class Ques {
public static void main(String[] args) throws FileNotFoundException {
double average = 0;
File inFile = new File("stationary.txt");
FileReader fileReader = new FileReader(inFile);
BufferedReader bufReader = new BufferedReader(fileReader);
File outFilel = new File("dearer.txt");
FileOutputStream outFileStreaml = new FileOutputStream(outFilel);
PrintWriter outStream1 = new PrintWriter(outFileStreaml);
File outFile2 = new File("cheap.txt");
FileOutputStream outFileStream2 = new FileOutputStream(outFile2);
PrintWriter outStream2 = new PrintWriter(outFileStream2);
computeAverage(bufReader, outStream1, outStream2, average);
}
public static void computeAverage(BufferedReader bufReader, PrintWriter outStream1, PrintWriter outStream2, double average) {
String line = "";
double mark = 0;
double sum = 0;
int count = 0;
try {
bufReader.readLine();
while ((line = bufReader.readLine()) != null) {
String [] data = line.split(" ");
mark = Double.parseDouble(data[2]);
sum += mark;
count++;
}
average = sum / count;
compareMark(outStream1, outStream2, average);
} catch (NumberFormatException | IOException e) {
System.out.println(e);
} finally {
if (bufReader != null) {
try {
bufReader.close();
} catch ( IOException e) {
e.printStackTrace();
}
}
}
}
public static void compareMark(PrintWriter outStream1, PrintWriter outStream2, double average) throws FileNotFoundException {
File inFile = new File("stationary.txt");
FileReader fileReader = new FileReader(inFile);
BufferedReader bufReader = new BufferedReader(fileReader);
String line = " ";
double sum = 0;
double mark = 0;
int count = 0;
try {
double ave = (double) Math.round(average * 100) / 100;
System.out.println("another " + ave);
bufReader.readLine();
while ((line = bufReader.readLine()) != null) {
System.out.println(line);
String [] data = line.split(" ");
mark = Double.parseDouble(data[2]);
if (mark > ave) {
System.out.println("Over");
outStream1.write(line);
} else {
System.out.println("Less");
outStream2.write(line);
}
}
} catch (IOException e) {
System.out.println(e);
} catch (NumberFormatException ex) {
System.out.println(ex);
} finally {
if (bufReader != null) {
try {
bufReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
The source code is perfectly working, just that I received 0 bytes of both files after executing reading twice (first, doing average and last, doing comparison). Why is that? what am I doing wrong here?
Thank you for your kind help.

Your code is not correct and does not compile. But the main flaws are the following:
Your Double.parseDouble(data[2]) shouldn't work with your 4th line of data. Better use Double.parseDouble(data[data.length - 1])
Remove the readLine()-calls in front of the while-loop.
Write the lines including a line separator.
Close the OutStreams

The Data File that you have provided have the columns seperated by a space. As the 2nd Column has data which contains spaces, the convertion of data[2] to double will trigger an exception. Which will make the program to close the buffers and exit.
Use Commas to seperate column data.
Use better exception handling to find exceptions easily.

All you need is to close those output stream. As you are using bufferredWriter and not flushing it after each write you need to close those output-stream. which will write back those lines or datas into the file. Here is an example how you can do it:
Example 1: using flush().
....
outStream1.write(line);
outStream1.flush();
} else {
System.out.println("Less");
outStream2.write(line);
outStream2.flush();
}
Example 2: most efficient (either way you need to close those buffer too like bufReader.close())
...
} catch (IOException e) {
System.out.println(e);
} catch (NumberFormatException ex) {
System.out.println(ex);
} finally {
// add try catch.
outStream2.close();
outStream1.close();
if (bufReader != null ... ) {
try {
bufReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

As requested, an example using List
First a class to hold the stationary data, must be completed:
public class Stationary {
private final int id; // or String if desired
private final String name;
private final double mark; // BigDecimal would be better for money
public Stationary(int id, String name, double mark) {
// TODO error checking
this.id = id;
...
}
public int getId() {
return id;
}
... // TODO other getters
// TODO equals, hashCode, toString
}
and to read the file:
public List<Stationary> read(File file) {
List<Stationary> list= new ArrayList<>();
try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
String line;
while ((line = reader.readLine()) != null) {
// TODO parse line into id, name, mark
list.add(new Stationary(id, name, mark);
}
}
return list;
}
now the list can be used as needed, e.g. average:
List<Stationary> stationaries = read(STATIONARY_FILE);
...
for (Stationary stationary : stationaries) {
sum += stationary.getMark();
count += 1;
}
...
streams not used to keep it simple

Java NoSuchElementException for Scanner in while loop [duplicate]

This question already has an answer here:
How to use java.util.Scanner to correctly read user input from System.in and act on it?
(1 answer)
Closed 7 years ago.
EDIT: While this issue has been marked as a duplicate, the other issue is different to my situation; it seems as though the program is ignoring this line:
decision = scan.nextInt();
I'm having some trouble with my scanner. I have a program that runs off a simple menu system.
The program works, but whenever it goes back to repeating the program again (I made the program have the ability to repeat by putting it in a while loop) it throws this error:
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:919)
at java.util.Scanner.next(Scanner.java:1542)
at java.util.Scanner.nextInt(Scanner.java:2172)
at java.util.Scanner.nextInt(Scanner.java:2131)
at GuardSearch.Menu(GuardSearch.java:29)
at GuardSearch.main(GuardSearch.java:8)
The program all works on the first run through the menu and its actions, but then when the call of the if statement is completed and the program returns to the while loop, it throws this exception. What am I missing?
I can post all the classes of the program if needed, however I believe my problem is within the following class:
import java.util.Scanner;
import java.lang.*;
public class GuardSearch {
public static void main(String[] args) {
Menu();
}
public static void Menu(){
Scanner scan = new Scanner(System.in);
boolean leave = false;
while(leave!=true){
final String ANSI_CLS = "\u001b[2J";
final String ANSI_HOME = "\u001b[H";
System.out.print(ANSI_CLS + ANSI_HOME);
System.out.flush();
int decision = 0;
System.out.println("Welcome to GuardSearch, our little slice of Google.\n");
while ((decision != 1) || (decision != 2)){
System.out.println("Please enter the number of what you would like to do from the following list:");
System.out.println("1. Submit knowledge.");
System.out.println("2. Search.");
System.out.println("3. Quit.");
decision = scan.nextInt();
if (decision == 1) {
Submit submit = new Submit();
submit.takeinfo();
break;
}
else if (decision == 2){
Search search = new Search();
search.takekeywords();
break;
}
else if (decision == 3){
leave = true;
break;
}
}
}
scan.close();
}
}
Thanks in advance. I have researched this issue and found no occurrences relevant to my exact issue.
EDIT: Here is my Submit and Search class as requested:
import java.io.*;
import java.util.Scanner;
public class Submit {
public static void takeinfo() {
final String ANSI_CLS = "\u001b[2J";
final String ANSI_HOME = "\u001b[H";
System.out.print(ANSI_CLS + ANSI_HOME);
System.out.flush();
System.out.println("Submit your knowledge to the system.\n");
Scanner sc = new Scanner(System.in);
int decision = 0;
while ((decision != 1) || (decision != 2)){
System.out.println("1. Change an existing article.");
System.out.println("2. Create a new article.");
System.out.println("3. Delete an article.");
System.out.println("4. Back.");
decision = sc.nextInt();
if (decision == 1) {
ChangeArticle chngArt = new ChangeArticle();
chngArt.takeinfo();
break;
}
else if (decision == 2){
CreateArticle createArt = new CreateArticle();
createArt.title();
break;
}
else if (decision == 3){
DeleteArticle deleteArt = new DeleteArticle();
deleteArt.takeinfo();
break;
}
else if (decision == 4){
GuardSearch gs = new GuardSearch();
gs.Menu();
break;
}
else {
System.out.println("Please enter a valid number.\n");
}
}
sc.close();
}
}
And the Search class:
import java.util.*;
import java.io.*;
public class Search {
Scanner sc = new Scanner(System.in);
public void takekeywords() {
final String ANSI_CLS = "\u001b[2J";
final String ANSI_HOME = "\u001b[H";
System.out.print(ANSI_CLS + ANSI_HOME);
System.out.flush();
System.out.println("Search the system.\n");
boolean fin = false;
int dec;
while (fin != true){
System.out.println("Please select which search type you want:\n");
System.out.println("1. Keywords.");
System.out.println("2. Category listing.");
System.out.println("3. Back\n");
dec = sc.nextInt();
if (dec == 1) {
// Do a keyword thing
fin = true;
}
else if (dec == 2) {
// Do a category thing
searchCategories();
fin = true;
}
else if (dec == 3) {
GuardSearch gs = new GuardSearch();
gs.Menu();
break;
}
}
}
public void searchCategories(){
// Create an empty list of subcategories, that will be added to when the user wants to add sub categories
LinkedList<Category> newSubCategories = new LinkedList<Category>();
// Create a list of .txt's relevant to the category
LinkedList<String> relevantArticles = new LinkedList<String>();
relevantArticles.add("example.txt");
LinkedList<String> dirListing = new LinkedList<String>();
//System.out.println("Please select your category:\n");
String s = "Example Category";
// Create the first category, passing in its name, an empty list of subCategories (which are of type Category), and a list of .txt's relevant to the category
Category firstCategory = new Category(s, newSubCategories, relevantArticles);
File wd = new File("/bin");
Process proc = null;
try {
proc = Runtime.getRuntime().exec("/bin/bash", null, wd);
}
catch (IOException e) {
e.printStackTrace();
}
if (proc != null) {
BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())), true);
out.println("cd /var/tmp/cholland/GuardSearch/");
out.println("ls *.art");
out.println("exit");
String line;
System.out.println();
try {
int x = 1;
while ((line = in.readLine()) != null) {
System.out.println(x + ") " + line);
dirListing.add(line);
x++;
}
System.out.println("Please select the article you want:\n");
int dec = sc.nextInt();
//System.out.println(Arrays.toString(dirListing.toArray()));
System.out.println(dirListing.size());
try {
for (int y=1; y<=dirListing.size(); y++) {
if (y == dec){
boolean fin = false;
while (fin != true){
System.out.println("You chose: " + (dirListing.get(boundIndex(y))) + ". Opening file...");
System.out.println("===========================================================\n");
String text;
String filepath = ("/var/tmp/cholland/GuardSearch/" + (dirListing.get(boundIndex(y))));
BufferedReader br = null;
StringBuffer contents = new StringBuffer();
try {
br = new BufferedReader(new FileReader(filepath));
text = null;
while ((text = br.readLine()) != null) {
contents.append(text).append(System.getProperty("line.separator"));
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
text = (contents.toString());
System.out.println(text);
System.out.println("\n===========================================================\n");
fin = true;
}
}
}
}
catch (Exception e) {
e.printStackTrace();
}
proc.waitFor();
out.close();
in.close();
proc.destroy();
}
catch (Exception e) {
e.printStackTrace();
}
}
sc.close();
}
public int boundIndex(int x){
if (x != 0){
return (x - 1);
}
else {
return 0;
}
}
}

I think the problem is here decision = scan.nextInt();
NoSuchElementException will be thrown if no more tokens are available. This is caused by invoking nextInt() without checking if there's any integer available. You can hasNextInt() to check if any more tokens are available.
Something like:
if(scan.hasNextInt() )
decision = scan.nextInt(); // if there is another number
else
decision = 0; // nothing added in the input

The cause of the error is that you are closing the scanner at the end of searchCategories.

Issue with using an array to store/print files from Linux

I cant figure out how to loop through this instead of just repeating the code, bugging the hell outta me! FYI assignment has already been turned in using 5 iterations of code, just wanted to learn how to implement the string array holding file contents into a for loop for future knowledge. I have tried for a few hours but it just prints the filename, cant seem to get the file contents.
/*************************************************************************
* LinuxSys.java
*
* This program reads text from a file
**************************************************************************/
import java.util.*;
import java.io.*;
public class LinuxSys {
public static void main (String[] args) {
String systemInfo[] = new String [5];
int i = 0;
// using _ to simulate file paths to test on local cpu, as it is easier/quicker
// than logging onto server/copy pasting code into new pico file
systemInfo[0] = "_proc_sys_kernel_hostname.txt"; //local files
systemInfo[1] = "_proc_meminfo.txt"; //local files
systemInfo[2] = "_proc_version.txt"; //local files
systemInfo[3] = "_proc_sys_kernel_hostname.txt"; //local files
//systemInfo[0] = "_proc_sys_kernel_hostname.txt"; //local files
// 1st try to print server host name file
try {
BufferedReader inputStream =
new BufferedReader(new FileReader(systemInfo[i]));
String line = "blank";
while (line != null) {
if((line = inputStream.readLine()) != null) {
System.out.println(line);
i++; // increment systemInfo[] array position
} // end if
} //end while
System.out.println(); // create space
inputStream.close();
} // end try
catch(FileNotFoundException e) {
System.out.println("File was not found");
System.out.println("or could not be opened");
} //end catch
catch(IOException e) {
System.out.println("Error reading from file");
} //end catch
// 2nd try to print server memory file
{
BufferedReader inputStream =
new BufferedReader(new FileReader(systemInfo[i]));
String line = "blank";
while (line != null) {
if((line = inputStream.readLine()) != null) {
System.out.println(line);
i++; // increment systemInfo[] array position
} // end if
} //end while
System.out.println(); // create space
inputStream.close();
} // end try
catch(FileNotFoundException e) {
System.out.println("File was not found");
System.out.println("or could not be opened");
} //end catch
catch(IOException e) {
System.out.println("Error reading from file");
} //end catch
// 3rd try to print version file
try {
BufferedReader inputStream =
new BufferedReader(new FileReader(systemInfo[i]));
String line = "blank";
while (line != null) {
if((line = inputStream.readLine()) != null) {
System.out.println(line);
i++;
} // end if
} //end while
System.out.println(); // create space
inputStream.close();
} // end try
catch(FileNotFoundException e) {
System.out.println("File was not found");
System.out.println("or could not be opened");
} //end catch
catch(IOException e) {
System.out.println("Error reading from file");
} //end catch
} // end main
} // end class

for(int i=0; i < systemInfo.size; ++i)
{
// the code you want to repeat with i varying each time
}
or
int i=0;
while(i < systemInfo.size)
{
// the code you want to repeat with i varying each time
++i;
}
or
int i=0;
while(i++ < systemInfo.size)
{
// the code you want to repeat with i varying each time
}
or
int i=0;
do
{
// the code you want to repeat with i varying each time
}
while(++i < systemInfo.size)
or...

How to get test questions from txt file with specific structure?

I want to make a program which get questions and their answers from file with specific structure and let the user give answers to them. The program also have to count right answers and show them to the user.
Here is the sample of the text file structure:
What year is it right now?
2
1) 1900
2) 2014
3) 3200
---
Which is the biggest country in the world?
1
1) Russia
2) United States of America
3) United Kingdom
---
That's the code I wrote, but there something wrong and I can't see what exactly is:
public class testLoader {
private static BufferedReader br;
private static int answerCounter;
public static void main(String[] args) {
try {
br = new BufferedReader(new FileReader("D:/test.txt"));
StringBuilder sb = new StringBuilder();
String line = br.readLine();
while (line != null) {
String answer=null;
if(line.startsWith("*")){
answer = line;
}
while (line != "---") {
line = br.readLine();
sb.append(line);
sb.append(System.lineSeparator());
}
System.out.println(sb.toString());
answerCheck(answer);
line = br.readLine();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
System.out.println("You have " + answerCounter + "correct answers");
}
public static void answerCheck(String rightAnswer) {
System.out.println("What's your answer?");
Scanner input = new Scanner(System.in);
String answer = input.nextLine();
answerCounter = 0;
if (answer == rightAnswer){
answerCounter++;
System.out.println("Correct!");
} else {
System.out.println("Wrong!");
}
}
}
I'll apreciate any help you can give. If there are any better way to complete the task, I'll be glad to see it.
Thanks in advance!

Here is the corrected version of your program.
You had a few bugs in there.
My program works OK on the file format you posted
here (without the asterisks that is).
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class testLoader {
private static BufferedReader br;
private static int answerCounter = 0;
public static void main(String[] args) {
try {
br = new BufferedReader(new FileReader("C:/Various/test.txt"));
StringBuilder sb = new StringBuilder();
String line = null;
do {
line = br.readLine();
if (line != null) {
sb.append(line);
sb.append(System.getProperty("line.separator"));
} else {
break;
}
String answer = br.readLine().trim();
while (!"---".equals(line)) {
line = br.readLine();
sb.append(line);
sb.append(System.getProperty("line.separator"));
}
System.out.println(sb.toString());
answerCheck(answer);
sb.setLength(0);
} while (true);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
System.out.println("You have " + answerCounter + " correct answers");
}
public static void answerCheck(String rightAnswer) {
System.out.println("What's your answer?");
Scanner input = new Scanner(System.in);
String answer = input.nextLine();
// answerCounter = 0;
if (answer.equals(rightAnswer)) {
answerCounter++;
System.out.println("Correct!");
} else {
System.out.println("Wrong!");
}
}
}

You want to seperate right answer from wrong ones with * sign but you are not providing it on your text file.
Even if you add * sign to the head of right answer, you won't make right answer value assigned to answer string variable.
Besides all of above, why do you want to check right answer with a * sign if you write the right answer's number below the question?
You have to compare strings with equals() method since you are dealing with values of strings, not memory addresses of them.
You have declared a StringBuilder object to append questions/answers and print them to screen but with this code, you will always add previous questions/answers to the current question. (i.e you are printing 2. question with first one above of it)
answerCounter variable will not hold user's total correct answers as you always assign it to 0 whenever you call the method.
So with all of these are corrected, I think you want to achieve something like below:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class testLoader
{
private static BufferedReader br;
private static int answerCounter = 0;
public static void main(String[] args)
{
try
{
br = new BufferedReader(new FileReader("C:/test.txt"));
StringBuilder sb;
String line, answer = null;
while((line = br.readLine()) != null)
{
sb = new StringBuilder();
do
{
if(line.length() == 1) //This is a bad choice of digit comparison but it will work with your case (lol)
{
answer = line;
line = br.readLine();
continue;
}
sb.append(line);
sb.append(System.lineSeparator());
line = br.readLine();
}
while(!line.equals("---"));
System.out.println(sb.toString());
answerCheck(answer);
}
}
catch(IOException e)
{
e.printStackTrace();
}
finally
{
try
{
br.close();
}
catch(IOException e)
{
e.printStackTrace();
}
}
System.out.println("You have " + answerCounter + "correct answers");
}
public static void answerCheck(String rightAnswer)
{
System.out.println("What's your answer?");
Scanner input = new Scanner(System.in);
String answer = input.nextLine();
if(answer.equals(rightAnswer))
{
answerCounter++;
System.out.println("Correct!");
}
else
{
System.out.println("Wrong!");
}
}
}