Not sure what I'm doing wrong

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I've tried this a few different ways and not sure what I'm missing. I'm receiving the longest string(s) each time. One solution I do not have commented in I created a second array list that only contained the longest string(s).

1. Initialize the list of strings.
2. Read 5 strings from the keyboard and add them to this list.
3. Using a loop, find the longest string in the list.
4. Display the string. If there is more than one, display each on a new line.

Requirements:

In the main method, initialize the Solution class's existing strings field to a new ArrayList<>.
The program should read 5 strings from the keyboard and write them to the list of strings.
The program should display the longest string.
If several strings qualify as the longest, then you need to display each of them on a new line.

package com.codegym.task.task07.task0708; import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.List; /* Longest string */ public class Solution { private static ArrayList<String> strings = new ArrayList<>(); public static void main(String[] args) throws Exception { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); int longestLength = 0; /** for(int i = 0; i < 5; i++){ strings.add(br.readLine()); if(strings.get(i).length() > longestLength) longestLength = strings.get(i).length(); } for(int i = 0; i < strings.size(); i++){ if(strings.get(i).length() == longestLength) System.out.println(strings.get(i)); } **/ for(int i = 0; i < 5; i++){ strings.add(br.readLine()); if(strings.get(i).length() > longestLength) longestLength = strings.get(i).length(); } int i = 0; while(i < strings.size()){ if(strings.get(i).length() != longestLength) strings.remove(i); else i++; } for(int j = 0; j < strings.size(); j++){ System.out.println(strings.get(j)); } } }

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John Yarab

Level 8 , United States

9 October 2019, 16:39

As a note when I move the Array list declaration to inside the main function i pass 3&4. However I understand this fails 1&2 since I was not allowed to change the declaration for the Array..... I keep messing about... and now the exact same code is failing #2 but doing a full println of the list shows 5 strings?

Guadalupe Gagnon

Level 37 , Tampa, United States

9 October 2019, 16:59

solution

did you use:

public static void main(String[] args) throws Exception {
   strings = new ArrayList<>();
   // rest of code
}

Guadalupe Gagnon

Level 37 , Tampa, United States

9 October 2019, 17:07

if that does not work, copy lines 17-34, reset the task, paste those lines back in, add that line of code above that I said to initialize the array, and make sure to remove comments. You should pass then.

John Yarab

Level 8 , United States

9 October 2019, 17:08

i declared and initialized it in the class

private static ArrayList<String> strings = new ArrayList<>();

not sure why moving the strings = new ArrayList<>(); to the main method was what was needed but it cleared it?

Guadalupe Gagnon

Level 37 , Tampa, United States

9 October 2019, 17:48

I wouldn't know, that is a question for CodeGym. Whoever programmed the verification checked for the initialization in the main method and not on a class level.

John Yarab

Level 8 , United States

9 October 2019, 18:02

Ok so more of a case wrong for the automated testing but not wrong in function. From a learning perspective would there be any real world implications to initializing in the class vs the function given the declaration had to stay in the class? I'm still a bit iffy on static object variables. Thanks again

Guadalupe Gagnon

Level 37 , Tampa, United States

9 October 2019, 19:53

useful

Generally speaking, you want to avoid using class and static variables where they are not called for. Because you are only using the list inside one method, it doesn't make sense to have it as a class variable. Something like the score in a game would be a good use of a class variable as many different game actions (meaning different methods in code) could affect the score and having it in one place makes sense. The static tag is a little more difficult. One clear use of it would be for constant variables (pardon the oxymoron), such as Integer.MAX_VALUE and MIN_VALUE. Programmers use constants because to help remember things, like the min and max values of an Integer: 2,147,483,647 and -2,147,483,648 ). Can you remember that number or MAX_VALUE easier? Also using constants is a great way to make changes in one place instead of multiple. Let's say you made a program that used a certain value multiple times in the code: double circ1 = 5 * 3.14; double circ2 = 6 * 3.14; double circ3 = 7 * 3.14; this is the circumference of a circle formula (diameter * Pi) with Pi being 3.14. Now later on if you want to change Pi to 3.14159 so that it is more accurate, you would have to change 3 lines of code. If you had it as a static: Static final double Pi = 3.14; double circ1 = 5 * Pi; double circ2 = 6 * Pi; double circ3 = 7 * Pi; You would only have to change 1 line of code. This is a small example, but if you could imagine a much larger program that used Pi in numerous different methods, having a static would save you a huge headache if you ever wanted to make a change.