It doesn't seem to print exit. I don't know why

Question about the task

Writing to a file from the console

Java Core, Level 3, Lesson 11

Resolved

1. Read a file name from the console.
2. Read lines from the console until the user enters the "exit".
3. Write all the entered lines to the file, each on a new line.

Requirements:

The program must read the file name from the console.
Create and use a BufferedWriter object.
The program should not read anything from the file system.
The program must read lines from the console until the user enters "exit".
The program must write absolutely all of the entered lines (including "exit") to the file, each on a new line.
The main method should close the BufferedWriter object after using it.

package com.codegym.task.task13.task1319; import java.io.*; /* Writing to a file from the console */ public class Solution { public static void main(String[] args) { // write your code here String fin = "exit"; BufferedReader entrada = null; BufferedWriter bufer = null; try { entrada = new BufferedReader(new InputStreamReader(System.in)); bufer = new BufferedWriter(new FileWriter(entrada.readLine())); while(true) { if(!entrada.readLine().equals("exit")) { bufer.write(entrada.readLine()); bufer.newLine(); bufer.flush(); } else { bufer.write("exit"); bufer.newLine(); bufer.flush(); break; } } } catch(FileNotFoundException e) { e.printStackTrace(); } catch(IOException e) { e.printStackTrace(); } finally { try { entrada.close(); bufer.close(); } catch(IOException e) { e.printStackTrace(); } } } }

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Thomas

Level 41 , Bayreuth, Germany

3 September 2023, 20:22

solution

Each time you invoke readLine() you read a new line from the console. And that's two times within every loop cycle (lines 25 and 27). The first read you just compare to 'exit'. If it does not match, you read another line and that you pass to the writer. While exception handling seems to be OK (except that you do not test for null before closing the streams), that way is pre Java 8 and much to elaborate. More modern is to use AutoClosable via try-with-resources. But I think Codegym doesn't require that at all. Just adding throws IOException to the main methods signature would do, too. Just a hint, if you need to do something in a loop before a condition needs to be tested, then you may consider a do-while loop. A possible approach may be: (as said, exception handling isn't really necessary even if you do nothing special. Outputting the stacktrace is somewaht the default - rethrowing the exception as RuntimeException does the same in the end)

try (BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
     BufferedWriter out = new BufferedWriter(new FileWriter(console.readLine()))) {

    String input;
    do {
        out.write(input = console.readLine());
        out.write(System.lineSeparator());
    } while (!input.equals("exit"));

} catch (IOException e) {
    throw new RuntimeException(e);
}

FelixUjo

Level 35 , Gijón, Spain

4 September 2023, 20:24

Thank you . I see the error.