# Java Array Tutorials
# Java Array Programs
➤ Count Even and Odd numbers in an Array
➤ Put Even and Odd Elements in 2 Separate Arrays
➤ Display Even and Odd numbers in an Array
➤ Sum of Even and Odd Numbers in Array in Java
➤ Remove odd numbers from an array java
➤ Count positive negative and zero from Array
➤ Print all negative elements in an array
➤ Separate positive and negative numbers in an array
➤ Find the sum of positive numbers in an array
➤ The cumulative sum of an array in Java
➤ Find numbers that are greater than the given number from an array
➤ Find average and numbers greater than average in array
Cumulative Sum of an Array in Java | Program Description:- Write a Java program to find the cumulative sum of an array. Take the array, find the cumulative sum, insert them in the same array, and display the result.
Example1:-
Array = {9, 8, 7, 0, -2, 5}
Cumulative sum = [9, 17, 24, 24, 22, 27]
Example2:-
Array = {-10, 5, 0, -9, 18, 27, -36}
Cumulative sum = [-10, -5, -5, -14, 4, 31, -5]
The cumulative sum is calculated as:- sum = sum + array[i]
Assume array = {9, 8, 7, 0, -2, 5}
sum = 0;
sum = 0 + 9 = 9
sum = 9 +8 = 17
sum = 17 +7 = 24
sum = 24 + 0 = 24
sum = 24 – 2 = 22
sum = 22 + 5 = 27
Procedure to develop the method to find the cumulative sum of an array in Java,
a) Take an array.
b) Declare a variable to store the sum value and initialize it with 0. Assume sum = 0.
c) Traverse through the array.
d) Calculate the sum value as, sum = sum + array[i]
e) Replace the sum value with array[i]
f) Return the array
Prerequisite:- Array in Java, find the length of an array in Java, different ways to print array in Java, find the sum of an array in Java
In this program, we will take the input value for the array from the end-user, but you can take it explicitly. See:- how to take array input in Java. We will use a method to perform the operation.
There are multiple ways to display an array but here we will use Arrays.toString() method given in java.util.Arrays class which is used to convert an array to String format. The java.util.Arrays class contains many methods related to array operations like sorting an array using sort(), copying an array copyOf() or copyOfRange(), searching an element in an array using binary search, and e.t.c. Learn more about:- Arrays class and methods in Java.
Java Program to Find Cumulative Sum of an Array
import java.util.Arrays;
import java.util.Scanner;
public class ArrayTest {
public static void main(String[] args) {
// create Scanner class object to take input
Scanner scan = new Scanner(System.in);
// read size of the array
System.out.print("Enter size of the array: ");
int n = scan.nextInt();
// create an int array of size N
int numbers[] = new int[n];
// take input for the array
System.out.println("Enter array elements: ");
for (int i = 0; i < n; ++i) {
numbers[i] = scan.nextInt();
}
// calculate the cumulative sum of array
int sum[] = cumulativeSum(numbers);
// display result
System.out.println("Cumulative sum = " + Arrays.toString(sum));
// close Scanner
scan.close();
}
// method to find cumulative sum of array
public static int[] cumulativeSum(int[] numbers) {
int sum = 0;
// traverse through the array
for (int i = 0; i < numbers.length; i++) {
sum += numbers[i]; // find sum
numbers[i] = sum; // replace
}
return numbers;
}
}
Output:-
Enter size of the array: 6
Enter array elements:
9 8 7 0 -2 5
Cumulative sum = [9, 17, 24, 24, 22, 27]
Enter size of the array: 7
Enter array elements:
-10 5 0 -9 18 27 -36
Cumulative sum = [-10, -5, -5, -14, 4, 31, -5]
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This is how I’ll write code if it’s for 20 marks.