Question

Hi Guys I have a text file that contains Amounts at Substring (34, 47) of each line. I need to sum Up all the Values to the End of the File. I have this code that I had started to build but I do not know how to proceed from here:

public class Addup {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) throws FileNotFoundException, IOException {
    // TODO code application logic here
    FileInputStream fs = new FileInputStream("C:/Analysis/RL004.TXT");
    BufferedReader br = new BufferedReader(new InputStreamReader(fs));
    String line;
    while((line = br.readLine()) != null){
        String num = line.substring(34, 47);

        double i = Double.parseDouble(num);
        System.out.println(i);
    }
}
}

The output is like this:

1.44576457E4
2.33434354E6
4.56875685E3

The Amount is in two decimal Places and I need the result also in the Two decimal Places. What Is the Best way to achieve this?

Answer 1

DecimalFormat is the best option to use:

double roundTwoDecimals(double d) {
            DecimalFormat twoDForm = new DecimalFormat("#.##");
        return Double.valueOf(twoDForm.format(d));
}

You can change your code to :

public static void main(String[] args) throws FileNotFoundException, IOException {
    // TODO code application logic here
    double sum = 0.0;
    FileInputStream fs = new FileInputStream("C:/Analysis/RL004.TXT");
    BufferedReader br = new BufferedReader(new InputStreamReader(fs));
    String line;
    while((line = br.readLine()) != null){
        String num = line.substring(34, 47);

        double i = Double.parseDouble(num);
        sum = sum + i;
        DecimalFormat twoDForm = new DecimalFormat("#.##");
        System.out.println(Double.valueOf(twoDForm.format(i)));
    }
        System.out.println("SUM = " + Double.valueOf(twoDForm.format(sum)));
}
}