But I am already showing the longest string?

Question about the task

Longest string

Java Syntax, Level 7, Lesson 6

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Can someone help me find out what I did wrong here?

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 List<String> strings; public static void main(String[] args) throws Exception { //write your code here BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); strings = new ArrayList<String>(); for(int i = 0; i<5; i++){ strings.add(reader.readLine()); } ArrayList<String> l = new ArrayList<String>(); l.add(strings.get(0)); for(int j = 1; j<strings.size();j++){ if(strings.get(j).length() > l.get(0).length() ){ l.set(0,strings.get(j)); } else if(strings.get(j).length() == l.get(0).length()){ l.add(strings.get(j)); } } for(int k =1; k<l.size(); k++){ if (l.get(k).length() < l.get(0).length()){ l.remove(k); } } for (String s : l) { System.out.println(s); } } }

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Davedabull

Level 22 , New York City, United States

18 November 2019, 13:41

solution: corrected the second to the last for block for(int k =1; k<l.size();){ if (l.get(k).length() < l.get(0).length()){ l.remove(k); System.out.println((l)); } else{ k++; } }

Maher Yousef

Level 13 , Amman, Jordan

18 November 2019, 10:12

there is Bugs in the code.you can try this code : public class Solution { private static ArrayList<String> strings; public static void main(String[] args) throws Exception { //write your code here int m = 0; String s ; strings = new ArrayList<String> (); BufferedReader reader = new BufferedReader( new InputStreamReader(System.in)); for(int i= 0 ; i<5 ; i++){ strings.add(reader.readLine()); s= strings.get(i); if (s.length() > m )m=s.length() ; } for(int i= 0 ; i<5 ; i++){ s= strings.get(i); if (s.length() == m) System.out.println(s); } } }

Davedabull

Level 22 , New York City, United States

18 November 2019, 13:36

Thank you!

Guadalupe Gagnon

Level 37 , Tampa, United States

18 November 2019, 04:35

Bug in the code. Try entering values like: "wow, win, that, chat, there"

Davedabull

Level 22 , New York City, United States

18 November 2019, 13:37

I see! So the problem is I tried to remove elements while I was iterating over the list. Thank you very much.

Guadalupe Gagnon

Level 37 , Tampa, United States

18 November 2019, 14:24

no. It is the way the code works. Your second for loop (line 27) puts elements into the second list if they are the same size as the 'base' word (which starts as the first word entered), then changing that 'base' word if the test word is larger. When entering in the words I propose, the second list would end up being: [there,win,chat] Now the third for loop (line 36) tests element k against elemtent 0, as k < 0, and removes element k if that returns true. The loop starts as i = 1. So this is how it proceeds: [there,win,chat] k(1):win < 0: there = true -- element k is removed - list now [there,chat] k = 2, list size = 2, loop breaks and no more checks are made. Results: there chat << this one is left behind and incorrect. What you are referring to is that you can not remove elements from a collection that you are iterating through using a foreach loop. This will throw a concurrent modification exception, and if left uncaught, will crash your code.

Davedabull

Level 22 , New York City, United States

18 November 2019, 15:42

I see. Thank you very much for the detailed explanation, I appreciate it! I modified the third for loop a bit and it works, can you check for me please? solution: for(int k =1; k<l.size();){ if (l.get(k).length() < l.get(0).length()){ l.remove(k); System.out.println((l)); } else{ k++; } }

Guadalupe Gagnon

Level 37 , Tampa, United States

18 November 2019, 15:49

That looks good to me. In the update, the index only moves when nothing is removed. Now it won't skip values.

Davedabull

Level 22 , New York City, United States

18 November 2019, 16:43

Awesome! Thank you!