not sure about the requirement.

Question about the task

Under discussion

i could verify in my local all working good. would be great if some one would able to find bug . @codegym task should pass if provided example is passing, would be my suggestion.

In the main method, read the name of a file that contains words separated by spaces from the console.
In the getLine method, use StringBuilder to order all the words as follows: the last letter of a word must match the first letter of the next word (ignore case).
Each word should be used once.
The getLine method can return any variant.
Separate words with a space.
Display the resulting string on the screen.

Example input file:

Okinawa Washington Auckland Kalamazoo Norfolk

Result:

Washington Norfolk Kalamazoo Okinawa Auckland

Requirements:

The main method must read the filename from the keyboard.
There should not be static fields in the Solution class.
The getLine method must use StringBuilder.
The getLine method must return an empty string (an empty StringBuilder) if it is not passed arguments (words).
The getLine method must not change the arguments (words).
All words passed to the getLine method must be included in the resulting string, if possible.
The screen output must match the task conditions.

package com.codegym.task.task22.task2209; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStreamReader; import java.util.LinkedList; import java.util.Scanner; public class Solution { public static void main(String[] args) throws IOException { //reading a file from inputs BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); //writing the debug on and off logic for testing locally or codegym site. boolean debug = false; //setting initally value to true to debug locally. String fileName; //string to save filename. if (debug) { fileName = "C:\\Users\\609631742\\OneDrive - BT Plc\\Notebooks\\or\\devops\\java-30-jan\\daily notes\\tet.txt"; } else { fileName = reader.readLine(); } FileInputStream fis = new FileInputStream(fileName); //reading the file and saving contents to stringBuilder Scanner sc = new Scanner(fis); StringBuilder sb = new StringBuilder(); if (sc.hasNext()) { sb.append(sc.nextLine()); } while (sc.hasNextLine()) { sb.append(" "); sb = sb.append(new StringBuilder(sc.nextLine())); } //To verify if string Builder is displayed correctly. // String stringInStringBuilder=sb.toString(); // System.out.println("Contents of StringBuilder: " + stringInStringBuilder); // StringBuilder result = getLine(); // System.out.println(result.toString()); //To display the contents of string after splitting it. // System.out.println("Splitting words with space and displaying to string: " + Arrays.toString(stringInStringBuilder.split(" "))); StringBuilder result = getLine(sb.toString().split(" ")); System.out.println(result.toString()); } public static StringBuilder getLine(String... words) { //to verify the size of passed arguments in getLine method //System.out.println("Displaying words size passed to getLine method: " + words.length); //to verify if arguments passed in getLine method are correctly displayed as expected. // System.out.println("Displaying words , which passed in getLine method for verification: "); StringBuilder stringBuilderReturning = new StringBuilder(); //added to pass codegym verification. //returning empty stringbuilder if arguments if null. if (words.length == 0) { return stringBuilderReturning; } //to get the size of words int wordsLength = words.length; LinkedList<String> stringLinkedList = new LinkedList<>(); //adding first word to List stringLinkedList.add(words[0]); //to check if there is any change in list and if no change break the loop. int oldListSize = stringLinkedList.size(); int newListSize = 0; //looping through untill linkedlist size is equal to words array size. if (wordsLength != 0) { while (oldListSize != newListSize) { oldListSize = stringLinkedList.size(); //looping through all words in words array for (int i = 0; i < wordsLength; i++) { //System.out.println(words[i]); //to check if word of array already exist in list , if yes then ignore. if (!stringLinkedList.contains(words[i])) { //to check if first letter of word equals to last letter of last word in list. //getting the first and last characters of word in array and list in all lower case. char firstCharInWords = Character.toLowerCase(words[i].charAt(0)); //first letter of word in word array char lastCharInList = Character.toLowerCase(stringLinkedList.getLast().charAt(stringLinkedList.getLast().length() - 1)); //last letter of word in list char lastCharInWords = Character.toLowerCase(words[i].charAt(words[i].length() - 1)); //first letter of word char firstCharInList = Character.toLowerCase(stringLinkedList.getFirst().charAt(0)); //to check if first letter of word equals to last letter of last word in list. if (firstCharInWords == lastCharInList) { stringLinkedList.addLast(words[i]); } else if (lastCharInWords == firstCharInList) { stringLinkedList.addFirst(words[i]); } } } newListSize = stringLinkedList.size(); } if (stringLinkedList.size() > 0) { stringBuilderReturning.append(stringLinkedList.get(0)); } for (int i = 1; i < stringLinkedList.size(); i++) { stringBuilderReturning.append(" "); stringBuilderReturning.append(stringLinkedList.get(i)); } } return stringBuilderReturning; } }

Comments (6)

Popular
New
Old

You must be signed in to leave a comment

Guadalupe Gagnon

Level 37 , Tampa, United States

16 October 2020, 15:03

useful

First, great job commenting your code, it was very easy to read and understand. Running a few tests it also seems to be working as intended. I have a a tip that may help you and one tip/idea that may let your code pass validation. So: #1 Tip: Take a look at this help question I made a few years ago: https://codegym.cc/help/1349 specifically I came up with a way to test the code by making a boolean "debug" that I could turn on and off. On being that the code behind the logic gate would be used for debugging purposes, while off meant all that code would be not be accessible and I could pass in the code for validation. This made it so I didn't need to comment out code used specifically for debugging. You may find it useful. #2 tip/idea The one thing I see that may be causing you to fail validation is that there is an extra space at the end of your output. You could just .trim() output, but I find that to be a lazy solution to clean coding. A method that I use, when building a String from many individual pieces, to ensure that it has the proper spaces is as such (this would be for lines 113-115 of your code):

// make sure there are strings first with an if statement, then add the string at index 0:
if(stringLinkedList.size()>0)
   stringBuilderReturning.append(stringLinkedList.get(0));

//add all remaining strings from index 1, prefixed with a space:
for(int i = 1; i < stringLinkedList.size(); i++)
   stringBuilderReturning.append(stringLinkedList.get(i));

Now the output StringBuilder would return a clean result.

Guadalupe Gagnon

Level 37 , Tampa, United States

16 October 2020, 15:03

useful

#3 Lines 27-30 should use the same logic as #2 to read lines, read the first line, then prefix a space to each additional lines, so it doesn't end up with an extra space at the end:

// check that there is something to read, then append
if(sc.hasNext()) sb.append(sc.nextLine());

// all additional appends should start with a space
while (sc.hasNextLine()) sb.append(" " + sc.nextLine());

Manish Sinha

Level 26 , london, United Kingdom

17 October 2020, 06:23

Thank you Guadalupe for your out of the box help. Reading one's code and providing suggestions in addition to query's answer is really appreciating.

Manish Sinha

Level 26 , london, United Kingdom

17 October 2020, 06:58

HI Guadalupe, i have implemented all the 3 tips. it is really making the code looks good and simple. Thank you. though not manage to find the bug.

Guadalupe Gagnon

Level 37 , Tampa, United States

17 October 2020, 15:30

ok, testing your code i did find a problem. In the case that there are duplicates of the same word, the output should have both of those words in it if it is possible to chain. For example if the file contained "racecar racecar", the output should be "racecar racecar", however line 96 would filter this out.

Manish Sinha

Level 26 , london, United Kingdom

18 October 2020, 05:17

thanks for pointing out the error. it seems duplicates complex the logic applied in program. i need to think of different way to do this.