Where is the error?

Question about the task

Under discussion

I have tried in a thousand ways and I can not get it to pass the tests. Please help.

The first parameter of the main method is a file name.
Display the ratio of the number of spaces to the number of all characters. For example, 10.45.
1. Count all the characters (n1).
2. Count the spaces (n2).
3. Display n2/n1*100, rounding to 2 decimal places.
4. Close the streams.

Requirements:

You don't need to read anything from the console.
Create a stream to read from the file passed as the first argument of the main method.
Calculate and display the ratio of the spaces to all characters in the file.
The displayed value must be rounded to 2 decimal places.
The stream used to read the file must be closed.

package com.codegym.task.task18.task1817; import java.io.FileInputStream; import java.io.FileReader; import java.io.IOException; /* Spaces */ public class Solution { public static void main(String[] args) throws IOException { int numberOfCharacters = 0; int numberOfSpaces = 0; double ratioSpacesOfAllTheCharacters = (double)numberOfSpaces/numberOfCharacters * 100; try (FileInputStream fileInputStream = new FileInputStream(args[0])) { int i; while(fileInputStream.available() > 0) { i = fileInputStream.read(); numberOfCharacters++; if ((char)i == ' ') numberOfSpaces++; } } System.out.print(Math.round(ratioSpacesOfAllTheCharacters)); } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

8 July 2022, 17:35

The code above has a logic error in that the line:

double ratioSpacesOfAllTheCharacters = (double)numberOfSpaces/numberOfCharacters * 100;

is before 'numberOfSpaces' and 'numberOfCharacters' are used to count the spaces and characters. This means that the line only uses their initial values of 0 that are set on the previous lines. With regards to your comment below: With doubles and floats dividing anything by 0 will result in NaN (Not a Number). With non-floating point number types (e.g. int, long, short) a division by 0 results in an unchecked arithmetic exception being created and thrown. The code below works with or without the 'if' check, however codegym might not accept solutions that output NaN, which adding the 'if' check prevents. If that is the case then codegym should definitely specify it in the task conditions that if there are no spaces then nothing should be output.

Korlat

Level 25 , Gasteiz, Basque Country, Spain

20 July 2022, 16:39

Thank you, now I see it clearly.

Korlat

Level 25 , Gasteiz, Basque Country, Spain

8 July 2022, 16:57

public class Solution {
    public static void main(String[] args) throws IOException {
        int numberOfCharacters = 0;
        int numberOfSpaces = 0;

        try (FileInputStream fileInputStream = new FileInputStream(args[0])) {

            while(fileInputStream.available() > 0) {
                int i = fileInputStream.read();
                numberOfCharacters++;
                if ((char)i == ' ') numberOfSpaces++;
            }

        }

        if (numberOfCharacters != 0) {
            double ratioSpacesOfAllTheCharacters = (double)numberOfSpaces/numberOfCharacters * 100;
            System.out.printf("%.2f" ,ratioSpacesOfAllTheCharacters);
        }
    }
}

Ok. I don't understand why but the error was in the "If". Without this line it didn't work for me.

if (numberOfCharacters != 0) {