CODEWITHSUNDEEP
java
vdtango
vdtango

Reputation: 37

Adding up all doubles in a loop, Java

So I have to create this program that reads a number of 'salaries' from a file, then adds all the salaries up to return one 'total salary' and also calculates the average of all the salaries.

The code I currently have is below:

package uploadTask7_countingSalaries;

//import utilities needed for the program
import java.util.Scanner;
import java.io.File;

public class countingSalaries {

    public static void main(String[] args) throws Exception { 
        // defines the file that data will be read from
        File salaryFile = new File("salaries.txt");
        // creates scanner object to read data from file
        Scanner scanFile = new Scanner (salaryFile);
        // creates while loop to read and print data to the user
        while(scanFile.hasNextDouble()) {
            double i = scanFile.nextDouble();
            System.out.println(i); }

        double addedSalary = scanFile.nextDouble();
        double sumofSalary = 0.0;
        while(scanFile.hasNextDouble()) {
            sumofSalary += addedSalary;
            addedSalary++; }

        System.out.println("Total salary is: " + addedSalary);

        }
    }

So far I've been able to read the salaries from the text file and print them out to the user. I'm struggling to find a way to add up all the numbers / calculate the average from the external file using a loop.

Upvotes: 0

Views: 2401

Answers (3)

Tacitus86
Tacitus86

Reputation: 1394

I would do it this way. It seems you are trying to iterate twice without resetting the iterator.

package uploadTask7_countingSalaries;

//import utilities needed for the program
import java.util.Scanner;
import java.io.File;

public class countingSalaries {

    public static void main(String[] args) throws Exception { 
        List<Double> salaries = new ArrayList<Double>();
        // defines the file that data will be read from
        File salaryFile = new File("salaries.txt");
        // creates scanner object to read data from file
        Scanner scanFile = new Scanner (salaryFile);
        // creates while loop to read and print data to the user
        while(scanFile.hasNextDouble()) {
            double i = scanFile.nextDouble();
            salaries.add(i);
            System.out.println(i); }

       double total = 0;
       for(double a : salaries){
        total = total + a;
       }

        System.out.println("Total salary is: " + total);
        System.out.println("Avg = " + total/salaries.size();

        }
    }

Upvotes: 1

krb
krb

Reputation: 347

Try this:

You need an additional int variable, that holds the number of salaries read , and then you can use this variable to calculate the average.

double addedSalary = scanFile.nextDouble();
            double sumofSalary = 0.0;
            int count = 0;
            while(scanFile.hasNextDouble()) {
                count ++;
                sumofSalary += addedSalary;
                addedSalary++; }
            double average = sumofSalary/ count;

            System.out.println("Total salary is: " + addedSalary);

Upvotes: 0

yevgeniy.batulin
yevgeniy.batulin

Reputation: 186

You have to sum up the salaries after reading each of them in your while loop so after each read you'll have a partial sum. After you get the sum, you can calculate the average based on the total sum and the count of elements you've read.

Upvotes: 0

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