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In this tutorial, you are going to learn to write a java program to find the sum of all array elements. We will see various approaches to perform the summation of array elements.

Example :

For input array arr=[2,4,1,3,6]

the output will be: 16

as 2+4+1+3+6 = 16

Program 1: Sum of an array using for loop in Java

• In the below program, we have used very simple approach to find the sum of array elements.
• First, we are taking the array size and array elements from the users.
• And using for loop we are iterating each element and performing addition on it.
• We have a sum variable to store the result of sum operation on each iteration.

import java.util.Arrays;
import java.util.Scanner;
public class Main {
   public static void main(String args[]){
      System.out.println("Enter the size of the array : ");
      Scanner s = new Scanner(System.in);
      int size = s.nextInt();
      int arr[] = new int [size];
      int sum = 0;
      System.out.println("Enter the array elements one by one ");
      for(int i=0; i<size; i++){
         arr[i] = s.nextInt();
         sum=sum+arr[i];
      }
      System.out.println("Sum of array elements: "+sum);
   }
} 

Output

Program 2 : Find Array Sum using Recursion in Java

• In the below program, we are using the recursion concept to find the sum of the array.
• To perform recursion we have a method name sum with parameters sum(int[] arr, int n), that are calling itself again and again.

import java.util.Arrays;
import java.util.Scanner;
public class Main {
   static int sum(int[] arr, int n)
   {
      if (n <= 0) {
        return 0;
      }
      return sum(arr, n - 1) + arr[n - 1];
   }
   public static void main(String args[]){
      System.out.println("Enter the size of the array : ");
      Scanner s = new Scanner(System.in);
      int size = s.nextInt();
      int arr[] = new int [size];
      System.out.println("Enter the array elements one by one ");
      for(int i=0; i<size; i++){
         arr[i] = s.nextInt();
      }
      int sumResult = sum(arr, arr.length);
      System.out.println("Array Elements are: "+Arrays.toString(arr));
      System.out.println("Sum of array elements: "+sumResult);
   }
}   

Output