Important Notice:

Practice-It will be discontinued as of November 1st, 2024. After this date, the website will remain online for a transitional period, but login will be restricted to University of Washington NetID authentication. This marks the next phase towards the platform's full retirement. Thank you for your use and support of the application over the years.

If you are looking for an alternative, a similar tool, CodeStepByStep, was developed independently by the original author of Practice-It, and is available at codestepbystep.com**

logo Practice-It logo

Main Page → Problems → Solve a Problem

BJP4 Exercise 15.5: runningTotal

Related Links:
Author: Marty Stepp (on 2016/09/08)

Write a method runningTotal that returns a new ArrayIntList that contains a running total of the original list. In other words, the i th value in the new list should store the sum of elements 0 through i of the original list. For example, if a variable list stores the following sequence of values: 

[2, 3, 5, 4, 7, 15, 20, 7]

and the following call is made: 

ArrayIntList list2 = list.runningTotal();

Then the variable list2 should store the following sequence of values: 

[2, 5, 10, 14, 21, 36, 56, 63]

The original list should not be changed by the method. If the original list is empty, the result should be an empty list. The new list should have the same capacity as the original. Remember that there is a constructor for ArrayIntList that takes a capacity as a parameter: 

// Constructs an empty list with the given capacity.
// Precondition: capacity >= 0
public ArrayIntList(int capacity)

Assume you are adding to the ArrayIntList class with following fields: 

public class ArrayIntList {
    private int[] elementData;
    private int size;

    // your code goes here
}
Type your solution here:


This is a partial class problem. Submit code that will become part of an existing Java class as described. You do not need to write the complete class, just the portion described in the problem.

You must log in before you can solve this problem.


Log In

If you do not understand how to solve a problem or why your solution doesn't work, please contact your TA or instructor.
If something seems wrong with the site (errors, slow performance, incorrect problems/tests, etc.), please

Is there a problem? Contact a site administrator.