I am confused. Only first condition is satisfied. It even fails to Read 10 lines from the keyboard and add them to the list.

Question about the task

Resolved

package com.codegym.task.task07.task0717;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.ListIterator;
/*
Duplicating words

*/

public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        ArrayList<String> list = new ArrayList<String>();
        for(int i = 0; i < 10; i++){
            list.add(br.readLine());
        }

        ArrayList<String> result = doubleValues(list);

        for(int i=0;i<result.size();i++){
            System.out.println(result.get(i));
        }
    }

    public static ArrayList<String> doubleValues(ArrayList<String> list) {
        ListIterator<String> itr = list.listIterator();

        while(itr.hasNext())
        {
            String s = itr.next();
            list.add(s);
        }
        return list;
    }
}

1. Read 10 words from the keyboard and add them to a list of strings.

2. The doubleValues method should duplicate words like this:
alpha, beta, gamma, -> alpha, alpha, beta, beta, gamma, gamma.

3. Display the result, each value on a new line.

Requirements:

Declare a string list variable and immediately initialize it.
Read 10 lines from the keyboard and add them to the list.
The doubleValues method should duplicate list elements like this: alpha, beta, gamma, -> alpha, alpha, beta, beta, gamma, gamma.
Display the resulting list, each element on a new line.

package com.codegym.task.task07.task0717; import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.ListIterator; /* Duplicating words */ public class Solution { public static void main(String[] args) throws Exception { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); ArrayList<String> list = new ArrayList<String>(); for(int i = 0; i < 10; i++){ list.add(br.readLine()); } ArrayList<String> result = doubleValues(list); for(int i=0;i<result.size();i++){ System.out.println(result.get(i)); } } public static ArrayList<String> doubleValues(ArrayList<String> list) { ListIterator<String> itr = list.listIterator(); while(itr.hasNext()) { String s = itr.next(); list.add(s); } return list; } }

Comments (2)

Popular
New
Old

You must be signed in to leave a comment

Djordje

Level 19

16 November 2018, 10:44

Thanks. Solved it with for loop. for(int i=0; i<list.size(); i+=2){ String s = list.get(i); list.add(i, s);

Roman

Level 41

16 November 2018, 08:58

Try to run your code. It doesn't work (java.util.ConcurrentModificationException).