In this example, we will see * “How to calculate average of N numbers in Java 8?”. *To achieve that, we are going to use Stream API introduced in Java 8 to find average and we will see it through several different ways.

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In this tutorial, we are going to cover below topics:

**How to calculate average of N numbers?****Different ways of calculating the average.**

Let’s begin:

**1. How to calculate average of N numbers?**

It’s very easy to find out the average. *Average has been calculated as sum of n numbers divided by n*.

**In order to calculate average, add all the numbers and divide them by count of numbers**.

**Let’s take an example, **

There are following numbers available: 7, 10, 81, 33, 69

And, we need to find the average of these numbers, what we need to do is:

**a.** First add all the numbers: (7+10+81+33+69) = **200**

**b.** Count the numbers: (7,10,81,33,69) = **5**

**c.** Find average by dividing a from b: **200 / 5** = **40**

**2. Different ways of calculating the average.**

## Example 1. Java 8 code to find average of numbers using List

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | import java.util.Arrays; import java.util.List; import java.util.OptionalDouble; /** * To calculate average of numbers using list in Java 8 * * @author D.V * */ public class Calculate_Average_Numbers_List_Of_Integers_Java8 { public static void main(String[] args) { List <Integer> listOfIntegers = Arrays.asList(20, 50, 99, 12, 94); OptionalDouble average = listOfIntegers .stream() .mapToInt(number -> number.intValue()) .average(); System.out.println("Average of Numbers: " + average); } } |

**Output:**

1 | Average of Numbers: OptionalDouble[55.0] |

## Example 2. Java 8 code to find average of numbers using Array

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | import java.util.Arrays; import java.util.OptionalDouble; import java.util.stream.IntStream; /** * To calculate average of numbers using Array in Java 8 * * @author D.V * */ public class Calculate_Average_Numbers_Array_Of_Integers_Java8 { public static void main(String[] args) { int[] arr = new int[10]; arr[0] = 20; arr[1] = 50; arr[2] = 99; arr[3] = 12; arr[4] = 94; arr[5] = 22; arr[6] = 43; arr[7] = 56; arr[8] = 55; arr[9] = 78; IntStream streamOfNumbers = Arrays.stream(arr); OptionalDouble averageOfNumbers = streamOfNumbers.average(); System.out.println("Average of Numbers: " + averageOfNumbers); } } |

**Output:**

1 | Average of Numbers: OptionalDouble[52.9] |

## Example 3. Java 8 code to find average of numbers using Array with Scanner

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 | import java.util.Arrays; import java.util.OptionalDouble; import java.util.Scanner; import java.util.stream.IntStream; /** * To calculate average of numbers using Array with Scanner in Java 8 * * @author D.V * */ public class Calculate_Average_Numbers_Array_Of_Integers_Using_Scanner_Java8 { private static Scanner scanner; public static void main(String[] args) { System.out.println("Enter how many numbers you want to use to calculate the average"); scanner = new Scanner(System.in); int number = scanner.nextInt(); int[] arr = new int[number]; System.out.println("\nEnter numbers now\n"); for (int i = 0; i < number; i++) { System.out.println("Enter number " + (i + 1) + ":"); arr[i] = scanner.nextInt(); } IntStream streamOfNumbers = Arrays.stream(arr); OptionalDouble averageOfNumbers = streamOfNumbers.average(); System.out.println("\nAverage of Numbers: " + averageOfNumbers); } } |

**Output:**

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | Enter how many numbers you want to use to calculate the average 5 Enter numbers now Enter number of subject 1: 6 Enter number of subject 2: 90 Enter number of subject 3: 55 Enter number of subject 4: 71 Enter number of subject 5: 11 Average of Numbers: OptionalDouble[46.6] |

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Deepak Verma is a Test Automation Consultant and Software development Engineer for more than 10 years. His mission is to help you become an In-demand full stack automation tester.

He is also the founder of Techndeck, a blog and online coaching platform dedicated to helping you succeed with all the automation basics to advanced testing automation tricks.