Be sure that after text is read in that the program displays all previously entered numbers, each number on a new line and in the same order that they were entered.

Question about the task

Method in a try-catch

Java Syntax, Level 9, Lesson 11

Under discussion

Could someone tell me what I am doing wrong? I am outputting the ArrayList items in a new line.

Write a program that will read numbers from the keyboard.
The code for reading numbers from the keyboard must be in the readData method.
Wrap the code inside readData in a try-catch block.
If the user enters text instead of a number, then the method should catch an exception and then display all previously entered numbers.
Display each number on a new line in the same order it was entered.

Requirements:

The program must read data from the keyboard.
Don't change the main method.
The main method should not throw exceptions.
The readData method must contain a try-catch block.
If the user enters text rather than a number, the program should display all previously entered numbers.

package com.codegym.task.task09.task0921; import javax.imageio.IIOException; import java.io.BufferedReader; import java.io.InputStreamReader; import java.text.ParseException; import java.util.ArrayList; import java.util.List; /* Method in a try-catch */ public class Solution { public static void main(String[] args){ try{ readData(); } catch(Exception e){ e.printStackTrace(); } } public static void readData() throws Exception { //write your code here ArrayList<Integer> list = new ArrayList<Integer>(); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); try { while(true){ int s = Integer.parseInt(reader.readLine()); list.add(s); } } catch (IIOException e){ for(int i= 0; i < list.size();i++){ System.out.println(list.get(i)); } e.printStackTrace(); } } }

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Sebastian

Level 18 , Malmoe, Sweden

17 April 2019, 19:12

Hi, In your main method you're trying to catch an exception, but that's what you're doing in the readData() method. In your while loop you can check if the next input is int, and I think you're catching the wrong exception. You'll also need to use the finally block to print the numbers that have been written. A code that passes the test can look like something like this:

public class Solution {
    public static void main(String[] args) {
        readData();
    }

    public static void readData() {
        //write your code here
        Scanner scanner = new Scanner(System.in);
        ArrayList<Integer> arrayList = new ArrayList<>();
        try{
            while (scanner.hasNextInt()){
                arrayList.add(Integer.parseInt(scanner.nextLine()));
            }
        }catch (NumberFormatException e){
            System.out.println(e);
        }
        finally {
            for (int inArr : arrayList){
                System.out.println(inArr);
            }
        }
    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

15 April 2019, 05:07

When a task asks you to print something to screen it needs to match exactly what the verification system expects. It does not ask you to print the stack trace.