code works fine with my files

Question about the task

Tracking changes

Java Core, Level 9, Lesson 11

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is it the try\catch block that's keeping it from validating?

Read 2 file names from the console: file1 and file2.
Both files contain text, but file2 is an updated version of file1. Some of the lines are still the same.
You need to create a merged version of the lines by writing them to the lines list.
The ADDED and REMOVED labels can't be used consecutively—they must always separated by the SAME label.
The example includes empty lines for clarity.
Neither the original file nor the updated file have empty lines!

Example 1:
original updated merged file1: file2: Result: (lines) line1 line1 SAME line1 line2 REMOVED line2 line3 line3 SAME line3 line4 REMOVED line4 line5 line5 SAME line5 line0 ADDED line0 line1 line1 SAME line1 line2 REMOVED line2 line3 line3 SAME line3 line4 ADDED line4 line5 line5 SAME line5 line0 REMOVED line0

Example 2:
original updated merged file1: file2: Result: (lines) line1 line1 SAME line1 line0 ADDED line0

In the example, empty lines mean that the line is not in the specified file.

Requirements:

The Solution class must contain a LineItem class.
The Solution class must have an enum called Type.
The Solution class must have a public static List<LineItem> field called lines that is initialized immediately.
In the main(String[] args) method, the program must read file names from the console (use BufferedReader).
In the main(String[] args) method, the BufferedReader used for reading input from the console must be closed after use.
The program must read the contents of the first and second file (use FileReader).
The file input streams (FileReader) must be closed.
The lines list should contain the merged version of the lines from the files. Each line should start with the label ADDED, REMOVED, or SAME, depending on the action taken.

package com.codegym.task.task19.task1916; import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.List; /* Tracking changes */ public class Solution { public static List<LineItem> lines = new ArrayList<>(); public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String file1 = reader.readLine(); String file2 = reader.readLine(); reader.close(); ArrayList<String> originalFile = new ArrayList<>(); ArrayList<String> updatedFile = new ArrayList<>(); BufferedReader reader2 = new BufferedReader(new FileReader(file1)); BufferedReader reader3 = new BufferedReader(new FileReader(file2)); while (reader2.ready()) { originalFile.add(reader2.readLine()); } while (reader3.ready()) { updatedFile.add(reader3.readLine()); } reader2.close(); reader3.close(); int a = 0; while (!originalFile.isEmpty() && !updatedFile.isEmpty()) { if (originalFile.get(a).equals(updatedFile.get(a))) { lines.add(new LineItem(Type.SAME, originalFile.get(a))); originalFile.remove(a); updatedFile.remove(a); //System.out.println("got here"); } else { try { if (originalFile.get(a).equals(updatedFile.get(a + 1))) { lines.add(new LineItem(Type.ADDED, updatedFile.get(a))); lines.add(new LineItem(Type.SAME, originalFile.get(a))); originalFile.remove(a); updatedFile.remove(a); updatedFile.remove(a); //System.out.println("got"); } if (originalFile.get(a + 1).equals(updatedFile.get(a))) { lines.add(new LineItem(Type.REMOVED, originalFile.get(a))); lines.add(new LineItem(Type.SAME, updatedFile.get(a))); originalFile.remove(a); updatedFile.remove(a); originalFile.remove(a); //System.out.println("tp"); } } catch (IndexOutOfBoundsException ignored) { } } } /*for (LineItem lineItem : lines) { System.out.println(lineItem.line + lineItem.type.toString()); }*/ /*for (int i = 0, i1 = 0, i2 = 1; i < originalFile.size() || i1 < updatedFile.size() && i2 < originalFile.size() && i2 < updatedFile.size(); i++, i1++, i2++) { try { if (originalFile.get(i).equals(updatedFile.get(i1))) { lines.add(new LineItem(Type.SAME, originalFile.get(i))); } else { if (originalFile.get(i).equals(updatedFile.get(i2))) { lines.add(new LineItem(Type.ADDED, updatedFile.get(i1))); lines.add(new LineItem(Type.SAME, originalFile.get(i))); i1++; } if (originalFile.get(i2).equals(updatedFile.get(i1))) { lines.add(new LineItem(Type.REMOVED, originalFile.get(i))); lines.add(new LineItem(Type.SAME, updatedFile.get(i2))); i++; } } }catch (IndexOutOfBoundsException e) { break; } } for (String s: originalFile ) { System.out.println(s); } for (String s: updatedFile ) { System.out.println(s); } for (LineItem lineItem: lines ) { System.out.println(lineItem.line + lineItem.type.toString()); }*/ } public static enum Type { ADDED, // New line added REMOVED, // Line deleted SAME // No change } public static class LineItem { public Type type; public String line; public LineItem(Type type, String line) { this.type = type; this.line = line; } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

14 September 2020, 15:50

solution

try the code with this data: file1: line one is going to be the same line two is going to be removed line three is going to be the same line four is going to be removed line five is going to be the same line seven is going to be the same file2: line one is going to be the same line three is going to be the same line five is going to be the same line six is going to be added line seven is going to be the same line eight is going to be added The correct addition to the 'lines' array would be: [LineItem{SAME - line one is going to be the same}, LineItem{REMOVED - line two is going to be removed}, LineItem{SAME - line three is going to be the same}, LineItem{REMOVED - line four is going to be removed}, LineItem{SAME - line five is going to be the same}, LineItem{ADDED - line six is going to be added}, LineItem{SAME - line seven is going to be the same}, LineItem{ADDED - line eight is going to be added}]

yehuda b

Level 23 , Beersheba, Israel

14 September 2020, 17:19

THANKS!!! I fixed it with adding: if (!originalFile.isEmpty()) { lines.add(new LineItem(Type.REMOVED, originalFile.get(0))); } else { if (!updatedFile.isEmpty()) { lines.add(new LineItem(Type.ADDED, updatedFile.get(0))); } } though it prob. isn't the most comprehensive solution being that I didn't get it all done in the while loop. But Guadalupe, I have one more question, How on earth did you figure that out? I understand the bug was that I only checked added\removed by it being the same afterwards, hence the last added \removed wasn't accounted for, but how did u figure that out, did you have some test cases ready? I have such a hard time cracking other peoples help questions! I wish I'd be able to analyze code so well......

Guadalupe Gagnon

Level 37 , Tampa, United States

14 September 2020, 17:47

I've been helping people on this site since 2018. It is not that I am exceptionally smart, or smarter than anyone else; its more that I have those years of experience debugging these tasks. Its the same concept in the work place with junior, mid level, and senior developers; I am just more of a senior level student. You'll get there, it just takes experience, and yes I failed a lot of these my first attempt, and a lot of them multiple times. So, with your code my process was simple: I copied your code into my intelliJ -> replaced user input (readline()) with static values, in this case the file names that pointed to that data (i have used these test values on this task in the past) -> added an output line at the very end of the main method to output "lines" ->then ran the code to check the result. After that I had to add a toString() method to the LineItem class to be able to have it display a human readable result, but then I found that your code passed when there was a line 9 in my test files, but not when I removed that line. Stepping through the code with the debugging tools starting after reading the data from the files. I found that after the line "line seven is going to be the same" was added to the result list, the array containing the lines from the first file was empty. This was causing line 36 to break the loop when there was still another value in the array containing the second files data that should have been added to the results list. After finding this I posted the hint that would expose where the code was stalling in hopes that you would find a fix, which you did, good job!!

yehuda b

Level 23 , Beersheba, Israel

14 September 2020, 19:36

Thanks again for this reply, I really appreciate the generosity with your time and mind-work. If I may further trouble you 1) I googled "static" not knowing the meaning of "static" values, and finally everything called static in java started making more sense to me, so thanks for that. 2) When you refer to debugging tools, what are they? I just remember the first (and only) time I posted a question on stackoverflow (which was downvoted 3 times in 5 minutes) some people suggested that too, is there a common tool\method for debugging? please don't spend time replying to this, I'll be happy with a good link :-) Thanks again! btw, Do you work in SW Dev. already? 'cause as much as I'm passionate about coding, I have a family I'd love to share my bounty with, and I have have a hard time finding direction after browsing through job requirements...... whatever, just be well.

Guadalupe Gagnon

Level 37 , Tampa, United States

14 September 2020, 20:28

i am actually an accountant who uses computer programming for fun, and to solve problems at work. I enjoy the problem solving aspect of it and at work I mostly create programs that do the repetitive, and time consuming, tasks for me. For the debugger you will want to set a break point, this is where the code will stop executing and give you line by line control -> then hit the debug button at the top -> when the code reaches the break point you can use the step button to move the process 1 line at a time (pic below).

Make a simple program like creating an array with the numbers 1-10 in it and add a break point on the first statement inside the main method, then step through it and notice how data is presented to you. It takes a little getting used to but it is worth it to learn.

yehuda b

Level 23 , Beersheba, Israel

14 September 2020, 20:53

Thanks! I checked out debugging on Intelij's website, though the step button I didn't realize, and the way you present it makes it easier for me to give it a try, I'll do the array idea you mentioned. I actually play minecraft for fun, programming is more of a brain gym session for me which I happen to enjoy, but like physical workouts I consider it more of a personal development thing than fun, I think it really is admirable to consider it in itself fun. I do happen to have 3 kids I want to support, and by consequence my programming passion is driven by additionally to the appreciation for computer science, technology, innovation, and machine stupidity vs. human who programmed it's intelligence, by the need to build myself a career, so thanks for brightening it up for me and many others and making it fun :-)