In this blog post, we will learn how to calculate the cumulative sum of elements in a Java array. The cumulative sum is the sum of all the previous elements in the array up to a certain index. This technique can be useful in various applications such as finance, data analysis, and statistics.

Table of Contents

• Introduction
• Approach
• Code Implementation
• Example Usage
• Conclusion

Introduction

The cumulative sum of an array element at index i is the sum of all the elements from index 0 to index i. For example, given an array [1, 2, 3, 4, 5], the cumulative sum at index 3 would be 1 + 2 + 3 + 4 = 10.

Approach

To calculate the cumulative sum of elements in a Java array, we can follow the steps below:

1. Create a new array of the same length as the original array to store the cumulative sums.
2. Initialize the first element of the new array with the value of the first element of the original array.
3. Iterate over the original array starting from the second element.
4. Add the current element to the cumulative sum of the previous element and store it in the corresponding index of the new array.
5. Repeat step 4 for all elements of the original array.

Code Implementation

public class CumulativeSum {
    public static int[] calculateCumulativeSum(int[] nums) {
        int[] cumulativeSum = new int[nums.length];
        cumulativeSum[0] = nums[0];
        for (int i = 1; i < nums.length; i++) {
            cumulativeSum[i] = cumulativeSum[i - 1] + nums[i];
        }
        return cumulativeSum;
    }
}

Example Usage

Let’s see an example of how to use the calculateCumulativeSum method:

int[] numbers = {1, 2, 3, 4, 5};
int[] cumulativeSum = CumulativeSum.calculateCumulativeSum(numbers);
System.out.println(Arrays.toString(cumulativeSum));

Output:

[1, 3, 6, 10, 15]

The resulting cumulativeSum array contains the cumulative sums at each index.

Conclusion

Calculating the cumulative sum of elements in a Java array can be done easily using a simple algorithm. By utilizing the cumulative sum, you can perform various calculations and analysis on your data. This technique is not only applicable to arrays, but also to other sequential data structures. So, the next time you need to calculate the cumulative sum, you can use the code provided in this blog post as a starting point.

#hashtags: #Java #array