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.
Java 8 programs to find average of n numbers...!!! Share on X
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
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:
Average of Numbers: OptionalDouble[55.0]
Example 2. Java 8 code to find average of numbers using Array
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:
Average of Numbers: OptionalDouble[52.9]
Example 3. Java 8 code to find average of numbers using Array with Scanner
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:
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]
Java 8 programs to find average of n numbers...!!! Share on X
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