Java sum of array

In this post, you will learn how to find the sum of an array using the Java programming language.

Java array is an object which contains elements of a similar data type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type.

Here, we mention different ways to calculate the sum of an array in Java.

Java find sum of array elements

First, we initialize an array arr and a variable sum and set the value of sum=0. To find the sum of all the elements in the array, we simply iterate the array using the for loop and add each element to the sum variable. After the termination of the loop, we print the value of the sum.

public class SumOfArray {  
    public static void main(String[] args) {  
        //Initialize array  
        int [] arr = new int [] {2,3,4,5,6,7};  
        int sum = 0;  
        //Loop through the array 
        for (int i = 0; i < arr.length; i++) {
           // calculate sum of elements  
           sum = sum + arr[i];  
        }  
        System.out.println("Sum of all the elements of an array: " + sum);  
    }  
} 

Sum of all the elements of an array: 15

Sum of array elements in java using scanner

In the given Java program, we ask the user to provide the size of an array and enter all the elements of that array. Then, we calculate the sum of elements of that array using a for loop.

import java.util.Scanner;
public class SumOfArray
{
    public static void main(String[] args) 
    {
        int n, sum = 0;
        Scanner scn = new Scanner(System.in);
        System.out.print("Enter no. of elements:");
        n = scn.nextInt();
        int arr[] = new int[n];
        System.out.println("Enter all the elements:");
        for(int i = 0; i < n; i++)
        {
            arr[i] = scn.nextInt();
            sum = sum + arr[i];
        }
        System.out.println("Sum of all the elements of array:"+sum);
    }
}

Enter no. of elements:5
Enter all the elements:
8 4 2 2 7
Sum of all the elements of array:23

Sum of array in Java using inbuilt function

Here, we call the of() method of the IntStream class to get a stream of array elements. And, then use the sum() method to get the sum of array in Java.

import java.util.stream.IntStream;

public class SumOfArray {  
    public static void main(String[] args) {  
        //Initialize array  
        int[] a = {8,4,2,2,7};
        int sum = IntStream.of(a).sum();
        System.out.println("Sum of all the elements of array: " + sum);
    }
}

Sum of all the elements of an array: 23

Find sum of array in Java 8 using stream() method

Java 8 introduces the Stream API. The Stream API provides many methods which can be pipelined to produce the desired result. We can use the sum() method of the Steam API to get a sum of all array elements.

import java.util.Arrays;
 
public class SumOfArray
{
    public static void main(String[] args)
    {
        int[] arr = {21,3,4,8,2};
        int sum = Arrays.stream(arr).sum();
 
        System.out.println("The sum of all the array elements: " + sum);
    }
}

The sum of all the array elements: 38

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