Calculate the Sum of Elements in an Array

Understanding Sum Calculation

Summing elements in an array involves adding all the elements together to get a total sum.

We will explore three different methods to calculate the sum of an array using Java.

Method 1: Using a Loop

This method iterates through the array and accumulates the sum.

public class SumArrayLoop {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        int sum = 0;
        
        for(int num : arr) {
            sum += num;
        }
        
        System.out.println("Sum: " + sum);
    }
}
            

Method 2: Using Recursion

This method calculates the sum recursively.

public class SumArrayRecursion {
    public static int sumRecursive(int[] arr, int n) {
        if (n == 0) return 0;
        return arr[n - 1] + sumRecursive(arr, n - 1);
    }
    
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        System.out.println("Sum: " + sumRecursive(arr, arr.length));
    }
}
            

Method 3: Using Streams

This method calculates the sum using Java Streams.

import java.util.Arrays;

public class SumArrayStream {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        int sum = Arrays.stream(arr).sum();
        
        System.out.println("Sum: " + sum);
    }
}