CodeGym/Help with Java Tasks/What is wrong here

Level 18

30.04.2020
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7comments

What is wrong here

Question about the task

Under discussion

My "Mentor" says I have too few lines.... BUT if I write "System.out.printLN(list)" I have too much lines XD Can someone please help ty

1. Read a file name from the console.
2. Read a set of numbers from the file.
3. Display only the even numbers, sorted in ascending order.

Example input:
5 8 -2 11 3 -5 2 10

Example output:
-2 2 8 10

Requirements:

The program must read data from the console.
The program must create a FileInputStream using the line read from the console.
The program should display data on the screen.
The program should display all of the even numbers read from the file, sorted in ascending order.
The program must close the input stream used to read the file (FileInputStream).

package com.codegym.task.task13.task1326; /* Sorting even numbers from a file */ import java.io.*; import java.util.ArrayList; import java.util.Collections; public class Solution { public static void main(String[] args) throws IOException { //write your code here BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); InputStream inputStream = null; BufferedInputStream buffer = null; try{ inputStream = new FileInputStream(reader.readLine()); buffer = new BufferedInputStream(inputStream); while (buffer.available()>0){ int i = (int)buffer.read(); if (i%2==0){ ArrayList<Integer>list = new ArrayList<>(); list.add(i); Collections.sort(list); System.out.print(list); }else{ } } }catch (Exception e){ } inputStream.close(); buffer.close(); reader.close(); } }

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WIDMO

Level 25 , Gdańsk, Poland

Expert

30 April 2020, 17:24

There are a few things I would change. First of all line 20 and 21 Iine to:

String fileName = reader.readLine();
FileInputStream fIS = new FileInputStream(fileName);
BufferedReader bR1 = new BufferedReader(new InputStreamReader(fIS));

This will allow you to use readLine() method. Next the declaration of list:

ArrayList<Integer> list = new ArrayList<>();

This should be done before loop that adds elements. The loop should be put in structure like this:

String s;
while ((s = bR1.readLine())!=null) {
    if (Integer.parseInt(s) % 2 == 0)
        list.add(Integer.parseInt(s));
}

Then you just have to sort the collection and print it on the screen :)

Benjamin

Level 18 , Bosnia and Herzegovina

30 April 2020, 18:59

I tried this but now i have 3 errors while before i had just one. I really dont know how to finish this maybe I'm tierd but i dont get this XD. But thank you any way. :)

WIDMO

Level 25 , Gdańsk, Poland

Expert

30 April 2020, 20:18

What error do u have now?

WIDMO

Level 25 , Gdańsk, Poland

Expert

30 April 2020, 20:19

can u send code?

Benjamin

Level 18 , Bosnia and Herzegovina

30 April 2020, 22:16

String fileName = reader.readLine(); FileInputStream fIS = new FileInputStream(fileName); BufferedReader bR = new BufferedReader(new InputStreamReader(fIS)); try { ArrayList<Integer> list = new ArrayList<>(); String s; while ((s = bR.readLine()) != null) { if (Integer.parseInt(s) % 2 == 0) { for (int i = 0; i < s.length(); i++) { list.add(i, Integer.parseInt(s)); } } Collections.sort(list); System.out.println(list); } } catch (Exception e) { // inputStream.close(); // buffer.close(); reader.close(); fIS.close(); bR.close(); } I have last 2 requirements in error and this msg "The program displays too many lines."

Nouser

Level 36 , Germany

30 April 2020, 22:55

you're closing the streams inside the catch block and

for (int i = 0; i < s.length(); i++) {
    list.add(i, Integer.parseInt(s));
}

why the loop? Do you want to add the number s.length times to the list

list.add(Integer.parseInt(s));

should do instead

Benjamin

Level 18 , Bosnia and Herzegovina

1 May 2020, 09:11

Thank you I managed last error but I'm at square one again... list either displays too few lines(print) or too much (println)...