One object of Scanner class?

Question

Hello, I was reviewing some posts and I found a very interesting question which was answered by db. I was hoping someone could answer this. The problem is that there can only be one instance of System.in. The OP posted code that has a instance in two separate places, both static methods. This was giving a no such element exception. DB suggested to make the declaration at the class level or to put it in main and pass it as a parameter.
OK long story short. I tried doing both of these things and couldnt get it to compile. Darryl if youre here can you complete this? Or if anyone else knows how to. Thanks
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package javaapplication38;
import java.util.Scanner;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.regex.Pattern;
import java.lang.*;
public class Main {
     * @param args
    public static void main(String[] args) {
// TODO Auto-generated method stub
        System.out.println("Welcome to lab exercise two");
        System.out.println("Please enter ten words pressing enter after each word");
        getInput();
        getFileName();
    protected static void getInput() {
        Scanner input = new Scanner(System.in);
        ArrayList<String> words = new ArrayList<String>();
        while (words.size() < 10) {
            System.out.println("Please enter word " + String.valueOf(words.size() + 1));
            String tempString = input.nextLine();
            StringTokenizer tempToks = new StringTokenizer(tempString);
            if (tempToks.countTokens() != 1) {
                System.out.println("Error: Please enter one word at a time, pressing enter after each word");
            } else {
                words.add(tempString);
        input.close();
    protected static void getFileName() {
        Scanner input = new Scanner(System.in);
        ArrayList<String> files = new ArrayList<String>();
        while (files.size() < 2) {
            System.out.println("Please enter file name " + String.valueOf(files.size() + 1) + " ,with format *.txt");
            String tempString = input.nextLine();
            StringTokenizer tempToks = new StringTokenizer(tempString);
            if (tempToks.countTokens() != 1) {
                System.out.println("Error: file name format error");
            } else {
                files.add(tempString);
        for (String fout : files) {
            System.out.println(fout);
        input.close();
}

Answer 1

Well, since your Scanner variable is declared as a local variable inside a method, it needs to initialize each time the method is called.
Do what I advised the other poster and put a declaration+initialization at the class level. Since your code as posted is totally non-OOP, you'll need to declare the var as static.import java.util.Scanner;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.regex.Pattern;
import java.lang.*;
public class Main {
   static Scanner input = new Scanner (System.in);
   public static void main (String[] args) {
      System.out.println ("Welcome to lab exercise two");
      System.out.println ("Please enter ten words pressing enter after each word");
      getInput ();
      getFileName ();
   protected static void getInput () {
      Scanner input = new Scanner (System.in);
      ArrayList<String> words = new ArrayList<String>();
      while (words.size () < 10) {
         System.out.println ("Please enter word " + String.valueOf (words.size () + 1));
         String tempString = input.nextLine ();
         StringTokenizer tempToks = new StringTokenizer (tempString);
         if (tempToks.countTokens () != 1) {
            System.out.println ("Error: Please enter one word at a time, pressing enter after each word");
         } else {
            words.add (tempString);
      input.close ();
   protected static void getFileName () {
      ArrayList<String> files = new ArrayList<String>();
      while (files.size () < 2) {
         System.out.println ("Please enter file name " + String.valueOf (files.size () + 1) + " ,with format *.txt");
         String tempString = input.nextLine ();
         StringTokenizer tempToks = new StringTokenizer (tempString);
         if (tempToks.countTokens () != 1) {
            System.out.println ("Error: file name format error");
         } else {
            files.add (tempString);
      for (String fout : files) {
         System.out.println (fout);
      input.close ();
}Let me know whether that works for you.
db