JAVA-从文本文件读取，识别新行

Question

I have a task to read a text file with several lines, after that I need to count every character's UNICODE value, so the sum of "hello" is 532 and for "how are you" is 1059 and so on, every string begins on new line in the .txt document and so far so good. But for every line I need to print only its own value, and the way my code works, it adds every line's value and I cant get my head around a way to stop it when the end of the lxtine comes so it looks something like: *read line *count char values *add up *print them *start over for the next line, and so

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.lang.String;
import java.util.Arrays;

public class SumLines {

    public static void main(String[] args) {

        String filePath = "/home/lines.txt"; 
        String readLine;
        int sum = 0;

        try (BufferedReader bufferedReader = new BufferedReader(new    FileReader(filePath))) {
            while ((readLine = bufferedReader.readLine()) != null) {
                char[] array = new char[readLine.length()];
                System.out.println(readLine);

                for (int i = 0; i < readLine.length(); i++) {

                    Arrays.fill(array, readLine.trim().charAt(i));
                    sum += (int) array[i];

                    System.out.print(sum + " ");
                }
            }
        } catch (IOException e) {
            System.out.println("Error.\n Invalid or missing file.");
            e.printStackTrace();
        }
       System.out.println("\n*** final " + sum);
    }
}

Answer 1

If I understood correctly, for the input:

 hello how are you 

You would like to get something like this as output:

 hello 532 how are you 1059 *** final 1591 

For this, you need to make some modifications to your code:

• In addition to calculating the sum of characters values per line, keep another sum of the total of all lines
• For each input line, print the line followed by the sum of character values
• You don't need an array at all
• It's better to trim the input line once, instead of for every character

Like this:

    int total = 0;

    try (BufferedReader bufferedReader = new BufferedReader(new    FileReader(filePath))) {
        String readLine;
        while ((readLine = bufferedReader.readLine()) != null) {
            String trimmed = readLine.trim();
            int sum = 0;
            for (int i = 0; i < trimmed.length(); i++) {
                sum += (int) trimmed.charAt(i);
            }
            System.out.println(readLine + " " + sum);
            total += sum;
        }
    } catch (IOException e) {
        System.out.println("Error.\n Invalid or missing file.");
        e.printStackTrace();
    }
    System.out.println("\n*** final " + total);

Answer 2

After your for loop, set sum to 0. If you want to print the total sum, then you need another variable, say t .

Like this:

for (int i = 0; i < readLine.length(); i++) {
    Arrays.fill(array, readLine.trim().charAt(i));
    sum += (int) array[i];
    System.out.print(sum + " ");
}
t=t+sum;
sum=0;

Then print t at the end.

Answer 3

A simple solution would be to limit the scope of the sum variable. That way, values will not persist between runs:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.lang.String;
import java.util.Arrays;

public class SumLines {

    public static void main(String[] args) {

        String filePath = "/home/lines.txt"; 
        String readLine;
        int totalSum = 0;

        try (BufferedReader bufferedReader = new BufferedReader(new    FileReader(filePath))) {
            String readLine;
            while ((readLine = bufferedReader.readLine()) != null) {
                int sum = 0;

                for (int i = 0; i < readLine.length(); i++) {
                    sum += (int) readLine.charAt(i);
                }

                System.out.println(readLine + ": " + sum);
                totalSum += sum;
            }
        } catch (IOException e) {
            System.out.println("Error.\n Invalid or missing file.");
            e.printStackTrace();
        }
       System.out.println("\n*** final " + totalSum);
    }
}

Also, you don't have to use such complicated stuff just to get the Unicode value of a char . I made some improvements.

Answer 4

Have two variables, one for final sum and one for line sum.

  public class SumLines {

public static void main(String[] args) {

    String filePath = "/home/lines.txt"; 
    String readLine;
    int totalSum = 0;
    int lineSum = 0

    try (BufferedReader bufferedReader = new BufferedReader(new    FileReader(filePath))) {
        while ((readLine = bufferedReader.readLine()) != null) {
            char[] array = new char[readLine.length()];
            System.out.println(readLine);

            for (int i = 0; i < readLine.length(); i++) {

                Arrays.fill(array, readLine.trim().charAt(i));
                lineSum += (int) array[i];

                System.out.print(lineSum + " ");
            }
            totalSum += lineSum + totalSum;
            lineSum = 0;
        }
    } catch (IOException e) {
        System.out.println("Error.\n Invalid or missing file.");
        e.printStackTrace();
    }
   System.out.println("\n*** final " + totalSum);
}

}