It works during tests, but won't pass verification.

Question about the task

Encryption

Java Core, Level 8, Lesson 11

Resolved

Any idea why it works perfectly when I test it, but won't pass verification?

Come up with an encryption/decryption mechanism.

The program runs with one of the following sets of arguments:
-e fileName fileOutputName -d fileName fileOutputName

where:
fileName is the name of a file to be encrypted/decrypted.
fileOutputName is the name of the file where you need to write the result of the encryption/decryption process.
-e indicates that you need to encrypt the data.
-d indicates that you need to decrypt the data.

Requirements:

You don't need to read anything from the console.
Create an input stream for the file passed as the second argument (fileName).
Create an output stream for the file passed as the third argument (fileOutputName).
In "-e" mode, the program should encrypt fileName and write the result to fileOutputName.
In "-d" mode, the program should decrypt fileName and write the result to fileOutputName.
The file streams must be closed.

package com.codegym.task.task18.task1826; /* Encryption */ import java.io.*; import java.util.ArrayList; public class Solution { public static void main(String[] args) throws IOException { switch (args[0]) { case "-e" : encryption(args[1], args[2]); //Encryption method break; case "-d" : decryption(args[2], args[1]); //decryption method break; default:break; } } public static void encryption(String fileName, String fileOutput) throws IOException { StringBuilder builder = new StringBuilder(); try (BufferedReader reader = new BufferedReader(new FileReader(fileName)); BufferedWriter writer = new BufferedWriter(new FileWriter(fileOutput))){ while (reader.ready()) { String data = reader.readLine(); builder.append(data); } char[] chars = builder.toString().toCharArray(); for (char i : chars) { i+=7; writer.write(i); } } } public static void decryption(String fileName, String fileOutput) throws IOException { StringBuilder builder = new StringBuilder(); try (BufferedReader reader = new BufferedReader(new FileReader(fileName)); BufferedWriter writer = new BufferedWriter(new FileWriter(fileOutput))){ while (reader.ready()) { String data = reader.readLine(); builder.append(data); } char[] chars = builder.toString().toCharArray(); for (char i : chars) { i-=7; writer.write(i); } } } }

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Jaime Padilla

Level 41 , Chandler, United States

Expert

16 November 2022, 21:45

Same results, but must be done a certain way or won't pass: - I had to rebuild it to not use BufferedReader or BufferedWriter. - I stupidly—although the description could be better— was decrypting the outsource file of the encryption. You know, to actually decrypt the message we encrypted. Don't do that! The decryption method needs to use args[1] for the fileName even though args[1] doesn't contain the encrypted message, but the original message that's not encrypted. It's supposed to work standalone. 😩

Jaime Padilla

Level 41 , Chandler, United States

Expert

16 November 2022, 21:36

solution

After 17 attempts of perfectly encrypting and decrypting through tests, this is what got it to pass:

public class Solution {
    public static void main(String[] args) throws IOException {

        switch (args[0]) {
            case "-e" : encryption(args[1], args[2]); //Encryption method
                break;
            case "-d" : decryption(args[1], args[2]); //decryption method
                break;
        }
    }
    public static void encryption(String fileName, String fileOutput) throws IOException {
        ArrayList<Character> list = new ArrayList<>();
        try (BufferedInputStream reader = new BufferedInputStream(new FileInputStream(fileName)); BufferedOutputStream writer = new BufferedOutputStream(new FileOutputStream(fileOutput))){
            int data;
            while ((data = reader.read()) != -1) {
                list.add((char) data);
            }
            for (char i : list) {
                i+=7;
                writer.write(i);
            }
        }
    }

    public static void decryption(String fileName, String fileOutput) throws IOException {
        ArrayList<Character> list = new ArrayList<>();
        try (BufferedInputStream reader = new BufferedInputStream(new FileInputStream(fileName)); BufferedOutputStream writer = new BufferedOutputStream(new FileOutputStream(fileOutput))){
            int data;
            while ((data = reader.read()) != -1) {
                list.add((char) data);
            }
            for (char i : list) {
                i-=7;
                writer.write(i);
            }
        }
    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

16 November 2022, 21:46

I just go here to check this question out, but it looks like you have figured it out.

Jaime Padilla

Level 41 , Chandler, United States

Expert

16 November 2022, 21:53

Appreciate you stopping by anyway, thank you!

Jaime Padilla

Level 41 , Chandler, United States

Expert

16 November 2022, 19:55

I changed it to accept multiple lines. Still wont pass

public class Solution {
    public static void main(String[] args) throws IOException {
        switch (args[0]) {
            case "-e" : encryption(args[1], args[2]); //Encryption method
                break;
            case "-d" : decryption(args[1], args[2]); //decryption method
                break;
        }
    }
    public static void encryption(String fileName, String fileOutput) throws IOException {
        StringBuilder builder = new StringBuilder();
        try (BufferedReader reader = new BufferedReader(new FileReader(fileName)); BufferedWriter writer = new BufferedWriter(new FileWriter(fileOutput))){
            while (reader.ready()) {
                String data = reader.readLine();
                builder.append(data);
                builder.append("\n");
            }
            char[] chars = builder.toString().toCharArray();
            for (char i : chars) {
                if (i == 10) {
                    writer.newLine();
                    continue;
                }
                i+=7;
                writer.write(i);
            }
        }
    }

    public static void decryption(String fileName, String fileOutputName) throws IOException {
        StringBuilder builder = new StringBuilder();
        try (BufferedReader reader = new BufferedReader(new FileReader(fileOutputName)); BufferedWriter writer = new BufferedWriter(new FileWriter(fileName))){
            while (reader.ready()) {
                String data = reader.readLine();
                builder.append(data);
                builder.append("\n");
            }
            char[] chars = builder.toString().toCharArray();
            for (char i : chars) {
                if (i == 10) {
                    writer.newLine();
                    continue;
                }
                i-=7;
                writer.write(i);
            }
        }
    }
}

Thomas

Level 41 , Bayreuth, Germany

16 November 2022, 08:28

try to switch arguments in your decryption method call (line 16)

Jaime Padilla

Level 41 , Chandler, United States

Expert

16 November 2022, 19:01

I've tried that and it still won't pass for some reason