Neon Number in JAVA

Neon Number :

A number whose sum of digits of square of the number is equal to the number is called neon number. For example, number 9 is a neon number as its square is 81 and the sum of the digits is 9. i.e. 9 is a neon number. There are only 3 neon numbers. They are 0, 1, and 9.

Example 1 : 9

      9

=>  9 * 9

=>   81
=>  8+1
=>  9 = Number = 9 , Hence 9 is a Neon number.

Example 2 : 1

      1

=  1 * 1

=   1 = 1 = Number, Hence 1 is an a Neon number.

Example 3 : 7

      7

=  7 * 7

=   49
= 4+9
=13  != 7 , Hence 7 is not a Neon number.

Algorithm to check whether a given number is a Neon Number or not:

Step 1: Accept a number.

Step 2: Calculate the square of a number and store it in a variable (say square).
Step 3: Find the sum of digits of the square of a number and store it in a variable (say sum).
Step 4: If the sum is equal to the accepted number then display "Neon number" else display "Not Neon Number".

Step 5: Stop

Sample Input and Output:

Input 1:    Enter number here --> 1
Output 1: The given number 1 is a Neon number

Input 2:    Enter number here --> 9
Output 2: The given number 9 is a Neon number

Input 3:    Enter number here --> 7
Output 3: The given number 7 is not a Neon number

Question: Write a program in java to check whether a given number is a Neon number or not.

The above Algorithm can be implemented in JAVA Programming in several ways. Some of the JAVA Program codes are given below:

Code 1: This is the general code to check for a Neon number in JAVA.

// Program to check whether a given number is a Neon number or not
import java.io.*;
public class neon {
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter number here --> ");
        int number = Integer.parseInt(in.readLine());
        int square = number * number;
        int sum = 0;
        while (square > 0) {
            int lastDigit = square % 10;
            sum = sum + lastDigit;
            square = square / 10;
        }
        if (sum == number)
            System.out.println("The given number " + number + " is a Neon number");
        else
            System.out.println("The given number " + number + " is not a Neon number");
    }
}

Code 2: This code accepts a number in String data type to check whether a given number is Neon number or not.

// Program to check whether a given number is a Neon number or not
import java.io.*;
public class neon1 {
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter number here --> ");
        String number = in.readLine();
        String square = Integer.toString((int) Math.pow(Integer.valueOf(number), 2));
        int sum = 0;
        for (int i = 0; i < square.length(); i++) {
            int currentDigit = square.charAt(i) - 48;
            sum = sum + currentDigit;
        }
        if (sum == Integer.valueOf(number))
            System.out.println("The given number " + number + " is a Neon number");
        else
            System.out.println("The given number " + number + " is not a Neon number");
    }
}

If you have any doubts/questions related to Program,  feel free to comment below.