No data in file when program runs - java

Question

my program works correctly in the sense that there are no compiling errors. Once I've been through the data and have entered some test data e.g. Firstname: Bob, Surname: Jones, Course: IT, Grade: 44. Firstly, it stores it in the "Grades.txt" file. However, when I re-run the program, the file resets and it's empty. Why is this? It is as if the data is only being temporarily stored in the file. Thanks

Code:

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.util.Scanner;

     public class ExamGrades {

    public static void main(String[] args) throws Exception {
        FileWriter grades = new FileWriter("grades.txt");
        BufferedWriter bw = new BufferedWriter(grades);
        PrintWriter out = new PrintWriter(bw);
        Scanner scan = new Scanner(System.in);

        int examMark =0;
        String firstName = "";
        String surName = "";
        String course = "";

            System.out.print("Please enter student firstname: ");
            firstName = scan.next();

            System.out.print("Please enter student surname: ");
            surName = scan.next();

            System.out.print("Please select student course: ");
            course = scan.next(); // Drop Down menu in future?

            System.out.print("Please enter student mark: ");
            while (!scan.hasNextInt())
            {
                System.out.print("Please enter a valid mark: ");
                scan.next();
            }
            examMark = scan.nextInt();

            if (examMark < 40)
            {
                System.out.println("Failed");
            }
            else if (examMark >= 40 && examMark <= 49)
            {
                System.out.println("3rd");
            }
            else if (examMark >= 50 && examMark <= 59)
            {
                System.out.println("2/2");
            }
            else if (examMark >= 60 && examMark <= 69)
            {
                System.out.println("2/1");
            }
            else if (examMark >= 70 && examMark <= 100)
            {
                System.out.println("1st");
            }
            else
            {
                System.out.println("Invalid Mark"); // If not within previous criteria, this prints
            }

        out.print(firstName + " ");
        out.print(surName + ", ");
        out.print(course + ", ");
        out.print(examMark);


        out.close();
        scan.close();
    }
}

score 2 · Answer 1 · answered Mar 13 '15 at 21:14

You need to pass true as the second parameter to the FileWriter constructor.

The second parameter that is accepted by the FileWriter constructor is named "append" and ensures that the FileWriter appends to the file instead of overwriting it.

For example:

FileWriter grades = new FileWriter("grades.txt", true);

No data in file when program runs - java

1 Answers1