Java - Adding specific indexes from arraylist using getters

Question

new java developer here so please bear with me.

I'm currently creating a basic program which will take user inputs and store them in an array list. There are some support logs in an array list and I am trying to calculate the sum of total hours spent from all support log entries.

This is my array list and the records:

import java.util.Scanner;
import java.util.ArrayList;

public class Main {

public static void main(String[] args) {

    Scanner scanner = new Scanner(System.in);


    ArrayList<User> listOfUsers = new ArrayList<>();
    ArrayList<Customer> listOfCustomers = new ArrayList<>();
    ArrayList<Logs> listOfLogs = new ArrayList<>();


    listOfUsers.add(new User("janedoe@gmail.com", "Jane Doe", "testABC"));

    listOfLogs.add(new Logs(11, 24, 05, 2018, 3, 280.04));
    listofLogs.add(new Logs(12, 12, 09, 2018, 4, 290.11));

the fifth values in the list are the hours (3 & 4 respectively).

This is what I tried at the moment but it didn't work:

if (menuOption == 5) {

    double sum = 0;
    for(int i = 0; i < l.getHours(); i++)
    sum += l.get(i);
    return sum;

}

my getter is as follows:

public int getHours() {
    return this.hours;
}

I will appreciate all support, thanks in advance.

EDIT: So after some answers have been posted, I have managed to iterate over the lists and get the values of the hours as follows:

  if (menuOption == 5) {

    for(Logs aLog : listOfLogs) {

        double sum = 0;

        sum += aLog.getHours();

        System.out.println(sum);      
    }
  }

I get the following output:

3.0
4.0

How do I add the values so that they would show as a total of "7.0" ?

Answer 1

You could try this:

if (menuOption == 5) {

                        double sum = 0;
                        for(int i = 0; i < listOfLogs.size() ; i++){
                        sum += listOfLogs.get(i).getHours();
                        }
                        return sum;

                    }

Changes made:

In the for loop i<(size of the listOfLogs List) which contains the Logs Object. Then, you have to iterate through each Logs instance and get the hours and add that to sum.