I'm stuck, I don't know where to go

Question about the task

Tracking changes

Java Core, Level 9, Lesson 11

Under discussion

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.*; 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 { ArrayList<String> line1 = new ArrayList<>(); ArrayList<String> line2 = new ArrayList<>(); String cadena1; String cadena2; BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String file1 = reader.readLine(); String file2 = reader.readLine(); reader.close(); BufferedReader bufer1 = new BufferedReader(new FileReader(file1)); while((cadena1 = bufer1.readLine()) != null) { line1.add(cadena1); } bufer1.close(); BufferedReader bufer2 = new BufferedReader(new FileReader(file2)); while((cadena2 = bufer2.readLine()) != null) { line2.add(cadena2); } bufer2.close(); for(int i = 0; i < line1.size(); i++) { if(line1.get(i).equals(line2.get(i))) { lines.add(new LineItem(Type.SAME, line1.get(i))); } else { if(line2.get(i).equals(line1.get(i+1))) { lines.add(new LineItem(Type.REMOVED,line1.get(i))); } else { lines.add(new LineItem(Type.ADDED, line2.get(i))); } } } } 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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Thomas

Level 41 , Bayreuth, Germany

27 November 2023, 07:47

You did not consider all possible cases. What if the files look like

A   A
B

A   A
    B

FelixUjo

Level 35 , Gijón, Spain

27 November 2023, 20:31

No idea, it's too complicated.

Thomas

Level 41 , Bayreuth, Germany

28 November 2023, 07:25

You already have written most of the needed code. Now it's finetuning. The current code you execute as long as both lists have next elements. That way you make sure that you do not run in exceptions when comparing a current element with the next of the other list. When both lists have no next element you're finished. If one of the lists has a next element you just need to decide if it is added or removed.