Java Display 10 multiples of a number and sum them

Question

On this program, it asks you a number, then displays 10 multiples of that number and then sums them but it has to be like this:

Number = 6;

06, 12, 18, 24, 30, 36, 42, 48, 54, 60

60, 54, 48, 42, 36, 30, 24, 18, 12, 06

Sum = 324

The part of displaying the numbers is no problem, the problem is when i have to sum them. I tried to use lists to save the numbers of each row and then use the first row/list and sum it but i can't get it to work.

    ArrayList<Integer> i1 = new ArrayList();
    ArrayList<Integer> i2 = new ArrayList();
    System.out.println("Introduce un número:\n"); // Asks you a number
    int n1=scan.nextInt();

    int add_i = 0;
    int rest_i = n1 * 11;

    i1.add(add_i);
    i2.add(rest_i);

    while (add_i <= n1 * 9) // while add_i is less or equal to n1 * 9
    {
        add_i += n1; // suma n1 a i
        System.out.print(i1 + "  "); // Prints the result
    }

    System.out.println("  ");

    while (rest_i >= 10) // while rest_i is greater or equal than 10
    {
        rest_i -= n1; // Resta n1 a i
        System.out.print(i2 + "  "); // Prints result
    }

Also in my program the mults do not show up.

Answer 1

Not sure what logic you are trying to undertake, but it seems a lot more difficult than

    Scanner scan = new Scanner(System.in);
    System.out.println("Enter number : ");
    int input = scan.nextInt ();
    int sum = 0;

    for (int loop = 1; loop <= 10; loop++) {
        int out = loop * input;
        sum += out;
        System.out.println(out);
    }

    // and down
    for (int loop = 10; loop >= 1; loop--) {
        int out = loop * input;
        System.out.println(out);
    }

    System.out.println("sum is "+ sum);

Answer 2

try this:

int sum = IntStream.iterate(startNumber, n -> n+startNumber)
  .limit(10)
  .peek(System.out::println)
  .sum();

Disclaimer because of downvotes. This is an alternate solution. You can look at it when you understand loops well enough I guess.