Java Ice Breakers

How to check whether a number is Disarium or not using stream

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by

anagendrakumar2020

in Java, Special numbers

This is the second solution to check the number for Disarium. This solution uses IntStream, reduce methods of Stream. The Disarium number is say for a given number 351, evaluate the powers from the left side as power (3 * 1) + power (5 * 2) + power (1 *3) , the sum of all powers must be equal to the given number 351.

import java.util.Scanner;
import java.util.stream.IntStream;

public class DisariumNumberUsingStream {

	public static void main(String args[]) {

		try (Scanner inpInt = new Scanner(System.in)) {
			System.out.print("Enter a number to check for Disarium or not=");
			int inpNum = inpInt.nextInt();
			System.out.println("The given number is=" + inpNum);
			String strVal = String.valueOf(inpNum);

			/*
			 * Applying map and reduce method to find out the sum of powers based on each
			 * digit position in the give number
			 */
			int sumOfPowerDigits = IntStream.range(0, String.valueOf(inpNum).length()).reduce(0,
					(x, y) -> x + (int) Math.pow(Character.getNumericValue(strVal.charAt(y)), y + 1));

			/* Check whether computed sum is equal to the actual number */
			if (sumOfPowerDigits == inpNum)
				System.out.println("The given number " + inpNum + " is an Disarium");
			else
				System.out.println("The given number " + inpNum + " is not an Disarium");
		}
	}
}

Output:
Enter a number to check for Disarium or not=518
The given number is=518
The given number 518 is an Disarium

Output:
Enter a number to check for Disarium or not=241
The given number is=241
The given number 241 is not an Disarium