What's wrong with the while loop?

thank you !! I have solved it... 19 attepts

Thank you for help! But I still can't pass the task before last one This is the new code .

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        FileReader fileReader = new FileReader(reader.readLine());
        FileWriter fileWriter = new FileWriter(reader.readLine());
        reader.close();
        fileReader.close();
        fileWriter.close();
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
        bufferedReader.close();
        bufferedWriter.close();

        String line = "";
        int count = 0;
        int t = Integer.parseInt(null);
        while ((line  =  bufferedReader.readLine() )!= null){
           String st = new String(line);
           String[] buff = st.split(" ");
           for (int i =0 ; i < buff.length ; i ++){
               if (isInteger(buff[i]))
                   t = Integer.parseInt(buff[i]);
                   //count++;
                  bufferedWriter.write(t+"\t");
           }
        }

is this beacause I have used "\t" ? I don't know how to write a space

import java.io.*; public class Help2 { public static boolean isInteger(String s){ try{ Integer.parseInt(s); return true; } catch (Exception e){ return false; } } public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String file1 = reader.readLine(); String file2 = reader.readLine(); reader.close(); BufferedReader fileReader = new BufferedReader(new FileReader(file1)); BufferedWriter fileWriter = new BufferedWriter(new FileWriter(file2)); while (fileReader.ready()){ String line = fileReader.readLine(); String words [] = line.split(" "); for(String s : words) { if(isInteger(s)) fileWriter.write(s + " "); } fileWriter.newLine(); } fileReader.close(); fileWriter.close(); } }

If it still not passed the conditions, create a new String in the for-loop and add every integer seperated by a whitespace charater and then call "s.trim()" after the loop has finished. And then write the whole line. Important is that you always have to call "writer.newLine()" when you write to a file because without this statement you would write all content in one line instead of different lines.

and dont close the readers and writers before you have used them

posting complete answers is not very welcome. Apart from that: I would put a bet on it that the verification will fail in line

fileWriter.write(s + " ");

--> additional space at the end

still, doesn't pass

yeah, I thought that this was the problem...writing the sapce but I can't figure what is wrong

I have used also your alternative...not working

could you append your current code again please? Otherwise it's difficult to see which issues already have been fixed and which are open. Niklas' code will not pass, if copy pasted, as it does not fulfill the requirements. The requirements say: separate by space. No newline or something.

yes

I have edited some lines....

public class Solution {
    String s= null;
    public static boolean isInteger(String s){
        try{
            Integer.parseInt(s);
            return true;
        }catch (Exception e){
            return false;
        }
    }
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        FileReader fileReader = new FileReader(reader.readLine());
        FileWriter fileWriter = new FileWriter(reader.readLine());
        reader.close();
        fileReader.close();
        fileWriter.close();
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
        bufferedReader.close();
        bufferedWriter.close();

       //String line = "";
       //String space = " ";
       //int t = Integer.parseInt(null);
      //while ((line  =  bufferedReader.readLine() )!= null){
      //   String st = new String(line);
      //   String[] buff = st.split(" ");

      //   for (int i =0 ; i < buff.length ; i ++){
      //       if (isInteger(buff[i])){
      //          // t = Integer.parseInt(buff[i]);
      //          System.out.println(buff[i]);
      //          bufferedWriter.write(buff[i]+space);
      //       }
      //   }
      //}
      while (bufferedReader.ready()){
          String line = bufferedReader.readLine();

          String words [] = line.split(" ");

          for(String s : words) {

              if(isInteger(s))
                  bufferedWriter.write(s + " ");
          }
          bufferedWriter.newLine();
      }
        bufferedReader.close();
        bufferedWriter.close();
    }
}

I got it. solved.