Task is giving expected result but validation s failing can you help

Question about the task

Under discussion

public class Solution { private static ArrayList<String> strings; static int c_len = 0, o_len = 0; public static void main(String[] args) throws Exception { strings = new ArrayList<>(); ArrayList<Integer> index = new ArrayList<>(); for (int i = 0; i < 5; i++) { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); strings.add(br.readLine()); } for ( int i = 0; i < strings.size(); i++){ c_len = strings.get(i).length(); if ( c_len > o_len ){ o_len = c_len; index.clear(); index.add(i); } else if(c_len == o_len){ index.add(i); } } for ( int j = 0; j < index.size(); j++){ System.out.println(strings.get(index.get(j))); } } }

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; static int c_len = 0, o_len = 0; public static void main(String[] args) throws Exception { strings = new ArrayList<>(); ArrayList<Integer> index = new ArrayList<>(); for (int i = 0; i < 5; i++) { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); strings.add(br.readLine()); } for ( int i = 0; i < strings.size(); i++){ c_len = strings.get(i).length(); if ( c_len > o_len ){ o_len = c_len; index.clear(); index.add(i); } else if(c_len == o_len){ index.add(i); } } for ( int j = 0; j < index.size(); j++){ System.out.println(strings.get(index.get(j))); } } }

Comments (6)

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Lisa

Level 41

20 January 2022, 10:25

There are two points I can imagine why validation fails. 1. You are using static variables. Validation is known to react sensible if you use statics (unless asked) 2. There's an edge case that is not handled properly. If you enter 5 times the empty string then (in my opinion) your code has to print an empty line 5 times. Overall your code works but you could make it even simpler. Just use one variable to save the max length. That max length of a string you can check whilst inputting the data. Then go through all entered strings, compare each length with the max length and if they equal -> output. Piece of cake :) Even the above mentioned edge case is handled automatically. You'd need to set one o_len to -1

Sajjad Ahmed

Level 10 , Bangalore, India

23 January 2022, 03:16

Hello, You an copy the code and execute it is working perfectly fine for all inputs. Even empty strings. Without declaring static one cannot use the variable in static context (public static void main). To confirm just print System.out.println(Somevriable) at the end . I executed both solution code and my code with similar input results are same.

Lisa

Level 41

23 January 2022, 09:15

I already did that and as stated above I only can see these 2 possibilities above that may the code not validate. As I did not write the validator I not know for sure if that's really the show stoppers. But you could try. Again... 1. Don't use static variables unless asked. My tasks often failed when I used them. The easiest alternative would be to use a local variable. That's a variable declared inside a method. For instance method (like you seem to have used) you'd need to instantiate an object. 2. That point may or may not get checked by the validator. But you easily can check that if you initialize o_len with -1 (as mentioned above). When you hit 5 times enter for the input then you'll get 5 empty lines as output (instead of the current no output) All you'd have to do is move line 15 to line 18, remove the static modifier and switch to -1 and try. If that does not work, then I suggested an alternative approach using a int max variable that just holds the max length instead of using a list to save the results, smth like that

int max = 0;
String input;
for (int i = 0; i < 5; i++) {
    strings.add(input = console.readLine());
    if (input.length() > max)
        max = input.length();
}

for (String s : strings)
    if (s.length() == max)
        System.out.println(s);

Guadalupe Gagnon

Level 37 , Tampa, United States

24 January 2022, 14:48

Lisa is correct: static variables cause failures in the validation system. That is just the way it is. Either way it is bad technique in Java to use static variables when a local variable is sufficient.

Sajjad Ahmed

Level 10 , Bangalore, India

29 January 2022, 00:55

Thank you . I think this part in code handle the empty strings. I don't need to assign o_len to -1 If c_len (current lenth of string ) == o_len(Old length of string) 0==0 Add it to integer array else if(c_len == o_len){ index.add(i); }

Lisa

Level 41

29 January 2022, 11:56

If that code does what CG expects then it is OK. There are literally thousands of possibilities to solve a task. Chose the one you think is the best (and maybe the one that your fellow programmers can understand when looking at it - that's then considered good code ;) ) But I can not see that your above code is doing what you expect. Or what's the deeper meaning in having the same conditions in if and else-if clauses? if (c_len == o_len) ... else if (c_len == o_len) ??? In any case you have recognized the problem and I'm sure you'll find a good solution.