Java Program to Calculate average using Array

We will see two programs to find the average of numbers using array. First Program finds the average of specified array elements. The second programs takes the value of n (number of elements) and the numbers provided by user and finds the average of them using array.

To understand these programs you should have the knowledge of following Java Programming concepts:
1) Java Arrays
2) For loop

Example 1: Program to find the average of numbers using array

public class JavaExample {

    public static void main(String[] args) {
        double[] arr = {19, 12.89, 16.5, 200, 13.7};
        double total = 0;

        for(int i=0; i<arr.length; i++){
        	total = total + arr[i];
        }


        /* arr.length returns the number of elements 
         * present in the array
         */
        double average = total / arr.length;
        
        /* This is used for displaying the formatted output
         * if you give %.4f then the output would have 4 digits
         * after decimal point.
         */
        System.out.format("The average is: %.3f", average);
    }
}

Output:

The average is: 52.418

Example 2: Calculate average of numbers entered by user

In this example, we are using Scanner to get the value of n and all the numbers from user.

import java.util.Scanner;
public class JavaExample {

    public static void main(String[] args) {
        System.out.println("How many numbers you want to enter?");
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        /* Declaring array of n elements, the value
         * of n is provided by the user
         */
        double[] arr = new double[n];
        double total = 0;

        for(int i=0; i<arr.length; i++){
        	System.out.print("Enter Element No."+(i+1)+": ");
        	arr[i] = scanner.nextDouble();
        }
        scanner.close();
        for(int i=0; i<arr.length; i++){
        	total = total + arr[i];
        }


        
        double average = total / arr.length;
        
        System.out.format("The average is: %.3f", average);
    }
}

Output:

How many numbers you want to enter?
5
Enter Element No.1: 12.7
Enter Element No.2: 18.9
Enter Element No.3: 20
Enter Element No.4: 13.923
Enter Element No.5: 15.6
The average is: 16.225