learnjava/FileInput.java at main · michaelkolesidis/learnjava · GitHub

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* File Input

* Take text file filename as argument and calculate the sum of the numbers.

* Each number should be on a seperate line.

* Use:

* $java FileInput numbers.txt

* numbers.txt:

* 1

* 2

* 3

* 4

* 5

* 6

* Output:

* Sum: 21.00

import java.io.File; // Import the File class

import java.io.FileNotFoundException; // Import this class to handle errors

import java.util.Scanner; // Import the Scanner class to read text files

public class FileInput {

public static void main(String[] args) {

try {

double sum = 0;

File file;

if (0 < args.length) {

String filename = args[0];

file = new File(filename);

} else {

System.out.println("Please enter filename");

return;

}

Scanner myReader = new Scanner(file);

while (myReader.hasNextLine()) {

double data = Double.parseDouble(myReader.nextLine());

sum += data;

}

myReader.close();

System.out.printf("Sum: %.2f\n", sum);

} catch (FileNotFoundException e) {

System.out.println("An error occurred.");

e.printStackTrace();

}

learnjava/FileInput.java at main · michaelkolesidis/learnjava · GitHub

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