I believe it's correct, but apparently not even the reading of the numbers is correct. Assistance, please!

Question about the task

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I have gone through multiple times and it seems fine to me. The only thing that MAYBE is not ok is that I add a space even at the end of the new file where I write the rounded numbers. But it doesn't say anywhere that there shouldn't be a space after the last number. Anyway, what is the problem? I can't figure it out?

Read 2 file names from the console.
The first file contains real (fractional) numbers, separated by spaces. For example, 3.1415.
Round the numbers to integers and write them, separated by spaces, to the second file.
Close the streams.

The rounding should work like this:
3.49 => 3
3.50 => 4
3.51 => 4
-3.49 => -3
-3.50 => -3
-3.51 => -4

Requirements:

The program should read a file name twice from the console.
Create an input stream for the first file. Create an output stream for the second file.
Read the numbers from the first file, round them, and write them to the second file, separated by spaces.
The rounding must be performed as indicated in the task.
The file streams must be closed.

package com.codegym.task.task18.task1820; /* Rounding numbers */ import java.io.*; public class Solution { public static void main(String[] args) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String fileName1 = br.readLine(); String fileName2 = br.readLine(); br.close(); FileInputStream fractionalNumbers = new FileInputStream(fileName1); FileOutputStream roundedNumbers = new FileOutputStream(fileName2); String numbersAndSpacesString = ""; //read all of the initial numbers (including spaces into a String); while (fractionalNumbers.available() > 0){ numbersAndSpacesString += Integer.toString(fractionalNumbers.read()); } //use split String [] numbers = numbersAndSpacesString.split("32"); int [] numbersRounded= new int[numbers.length]; //round them for (int i = 0; i < numbers.length; i++){ numbersRounded[i] = (int) Math.round(Double.parseDouble(numbers[i])); roundedNumbers.write(numbersRounded[i]); roundedNumbers.write(32); } fractionalNumbers.close(); roundedNumbers.close(); } }

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Dmitri

Level 22 , Seversk, Russia

20 January 2021, 11:15

in your comment you say //read all of the initial numbers (including spaces into a String); but Integer.toString(fractionalNumbers.read()) would read byte by byte, convert to int, then to String and then add up to the String variable, the reading won't be number by number. It is more convenient to use BufferedReader and .readLine(), and then .split(" ") in the end you can remove space by .trim()

Guadalupe Gagnon

Level 37 , Tampa, United States

19 January 2021, 15:10

useful

This code reads in each byte and converts the byte's code to a String. With a file such as: 3.49 3.50 3.51 -3.49 -3.5 -3.51 The result of "numbersAndSpacesString" would be: 51465257325146534832514653493245514652573245514653324551465349 While the result of splitting that by "32" for line 27 would be: [51465257, 51465348, 51465349, 4551465257, 45514653, 4551465349] These are the bytes for the fractional numbers in the file, but the computer does not know that. You will need to convert them properly into the fractional numbers before the loop at line 31 is reached. I recommend that you use a Scanner for input because the methods available would do this for you.

Andrei

Level 41

19 January 2021, 17:06

I have adapted the code, when testing with SOUT it prints correctly, however, when I open the file where the numbers were written, there's some jibberish in it. " ý ý ü " I don't understand why it is not writing correctly the ints to the file

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String fileName1 = br.readLine();
        String fileName2 = br.readLine();
        br.close();

        FileInputStream fileInputStream = new FileInputStream(fileName1);
        Scanner fractionalNumbers = new Scanner(fileInputStream);
        FileOutputStream roundedNumbers = new FileOutputStream(fileName2);

        List<Double> doubles = new ArrayList<>();

        //adding to an ArrayList all of the doubles using the nextDouble method which discards whitespace
        //by default
        while (fractionalNumbers.hasNext()){
                doubles.add(fractionalNumbers.nextDouble());
        }

        //iterating through the array to round the doubles
        for (Double printNumber : doubles){
            //need to round the double , convert to int, byte and write to fileName2
            int roundedNumber = (int) Math.round(printNumber);

            //here I am writing the rounded double casted to an int to file2.
            roundedNumbers.write(roundedNumber);
            //adding space
            roundedNumbers.write(32);

            //System.out.print(roundedNumber);
        }

        fileInputStream.close();
        fractionalNumbers.close();
        roundedNumbers.close();
    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

19 January 2021, 17:23

solution

This is because you are using a FileOutputStream to output ints. It would be, and is, writing in ascii code. Try writing the output number as a byte[] of the String value of the rounded number.

Andrei

Level 41

27 January 2021, 18:00

I'm sorry but I can't really understand. You mean in line 23 to turn Math.round(printNumber) into a String and then put that String into a byte[] ? And then write that byte[] to fileName2 ? L.E. I tried like this and it worked! Here is the updated bit:

for (Double printNumber : doubles){
           //need to round the double , convert to int, byte and write to fileName2
           String roundedNumber = Integer.toString((int) Math.round(printNumber));
           byte[] roundedNumberToBytes = roundedNumber.getBytes();
           //here I am writing the rounded double casted to an int to file2.
           roundedNumbers.write(roundedNumberToBytes);
           //adding space
           roundedNumbers.write(32);

Guadalupe Gagnon

Level 37 , Tampa, United States

27 January 2021, 18:25

useful

Let's say that you had a double that was: 55.24 Line 23 would round that to 55. Line 26 will write then write 55 to the file... but just like line 28 doesn't write the number 32 to the file, line 26 won't write "55" to the file. Instead it will write the char '7', which is what 55 is in ASCII (32 is space in ASCII).

Guadalupe Gagnon

Level 37 , Tampa, United States

27 January 2021, 18:28

I see you updated it too, and you got it! The getBytes() method will return a byte[] that corresponds to the ASCII number of each individual character in a String. When passed to the write() method it will then print each character correctly as intended.