neon number

A neon number is a number where the sum of digits of square of the number is equal to the number. The task is to check and print neon numbers in a range.

Examples: 

Input : 9
Output : Neon Number
Explanation: square is 9*9 = 81 and 
sum of the digits of the square is 9.

Input :12
Output : Not a Neon Number
Explanation: square is 12*12 = 144 and 
sum of the digits of the square is 9 (1 
+ 4 + 4) which is not equal to 12.

The implementation is simple, we first compute square of given number, the find sum of digits in the square.

// Java program to check and print
// Neon Numbers upto 10000
import java.io.*;

class GFG {
	// function to check Neon Number
	static boolean checkNeon(int x)
	{
		// storing the square of x
		int sq = x * x;

		// calculating the sum of digits
		// of sq
		int sum_digits = 0;
		while (sq != 0) {
			sum_digits = sum_digits + sq % 10;
			sq = sq / 10;
		}
		return (sum_digits == x);
	}

	// Driver Code
	public static void main(String args[])
						throws IOException
	{
		// Printing Neon Numbers upto 10000
		for (int i = 1; i <= 10000; i++) 
			if (checkNeon(i))
				System.out.print(i + " ");	 
	}
}
// This code is contributed by Nikita Tiwari.