Question

I don’t understand why these two implementations produce different results?

Method with expected results:

    private void writeToFile(WorkoutLog log){
        try {
        BufferedWriter out = new BufferedWriter(new FileWriter("src/exercise/textfile2.txt", true));

        out.write(log.name.toString() + ", " + log.type + ", " + log.duration + ", " + log.caloriesburned + "\n");
        out.close();
    }catch (IOException e) {  
        System.out.println("error writing record to text file " + e );
    }
}

data file result

jim, 1, 123, 246

mike, 3, 12, 24

jim, 4, 50, 100

joni, 5, 40, 80

Method with unexpected result:

    private void writeToFile2(WorkoutLog log){
    try {
        BufferedWriter out = new BufferedWriter(new FileWriter("src/exercise/textfile2.txt", true));

        out.write(log.name.toString());
        out.write(", ");
        out.write(log.type);
        out.write(",");
        out.write(log.duration);
        out.write(",");
        out.write(log.caloriesburned);
        out.write("\n");
        out.close();
    }catch (IOException e) {  
        System.out.println("error writing record to text file " + e );
    }
}

data file result

joe, , ,@

fred, ,{,ö

Why is breaking the out.write statements onto separate lines causing the output to produce odd results? Each method is being passed an array reference with object that stores the result to write as string, short, short short data types.

Answer 1

I assume that log.type, log.duration and log.caloriesburned are int values, which means you’re calling the BufferedWriter.write(int) overload. That just writes a single character. I suspect you just need:

out.write(log.name.toString());
out.write(", ");
out.write(String.valueOf(log.type));
out.write(",");
out.write(String.valueOf(log.duration));
out.write(",");
out.write(String.valueOf(log.caloriesburned));
out.write("\n");

Note that you should close the writer in a finally block so that it gets closed even if there’s an exception.