Help, please!

Question about the task

Duplicating words

Java Syntax, Level 7, Lesson 9

Under discussion

What's it doing?!

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; /* Duplicating words */ public class Solution { public static void main(String[] args) throws Exception { // Read strings from the console and declare an ArrayList here BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); ArrayList<String> list = new ArrayList<String>(); ArrayList<String> result = doubleValues(list); for (int i = 0; i<10; i++) { String s = reader.readLine(); list.add(s); //int x = String.parseString(s); } System.out.println(list); // Display result System.out.println(doubleValues(list)); } public static ArrayList<String> doubleValues(ArrayList<String> list) { //write your code here ArrayList<String> result = new ArrayList<String>(); int counttt = 0; for (/*a thing is in here ok.*/ int i = 0; i < list.size(); i++){ //vresult.add(i, list.get(i)); //System.out.println(i+1); for (/*a thing is in here ok.*/ int j = 0; j < 3; j++){ result.add(i, list.get(i)); //System.out.println(i+1); //} } } return result; //return null; } } // int counttt = 0; // for (/*a thing is in here ok.*/ int i = 0; i < list.size(); i++){ // result.add(i, list.get(i)); // //System.out.println(i+1); // for (/*a thing is in here ok.*/ int j = 0; j < 1; j++){ // result.add(i+1, list.get(i)); // //System.out.println(i+1); // //} // } /* oldmessedupcodethatishouldvenevermadeabeginonit.java package com.codegym.task.task07.task0717; import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.ArrayList; Duplicating words public class Solution { public static void main(String[] args) throws Exception { // Read strings from the console and declare an ArrayList here BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); ArrayList<String> list = new ArrayList<String>(); ArrayList<String> result = doubleValues(list); // Display result } public static ArrayList<String> doubleValues(ArrayList<String> list){ //write your code herevg BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); for (int i = 0; i < list.size(); i++){ String s = reader.readLine(); list.add(s); //int x = String.parseString(s); } for (String s : list) { System.out.println(s); System.out.println(s); } return null; } } */

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Gellert Varga

Level 23 , Szekesfehervar, Hungary

3 February 2021, 23:26

This is your program. I just added two new commands to see in which round how changed the "result" ArrayList. Run it, with these strings as an input list: a, b, c, d, e, f, g, h, j, k, and i think you will be able to analyze the working of program.

import java.io.*;
import java.util.ArrayList;

public class Solution {
    public static void main(String[] args) throws Exception {

        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        ArrayList<String> list = new ArrayList<String>();
        ArrayList<String> result = doubleValues(list);
        for (int i = 0; i<10; i++)
        {
               String s = reader.readLine();
               list.add(s);
        }

        System.out.println(list);
        System.out.println(doubleValues(list));
    }

    public static ArrayList<String> doubleValues(ArrayList<String> list) {

        ArrayList<String> result = new ArrayList<String>();
        int counttt = 0;

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

            for (int j = 0; j < 3; j++){
                result.add(i, list.get(i));
                System.out.println(result);
            }
        }
        return result;
    }
}