Neon Number - GeeksforGeeks

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.

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

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

C++

// C/C++ program to check and print 
// Neon Numbers upto 10000 
#include <iostream> 
using namespace std; 
#include <math.h> 
  
int checkNeon(int x) 
{ 
    // storing the square of x 
    int sq = x * x; 
  
    // calculating the sum of 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 
int main(void) 
{ 
    // Printing Neon Numbers upto 10000 
    for (int i = 1; i <= 10000; i++)  
        if (checkNeon(i)) 
            cout << i << " ";     
} 

Java

// 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 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. 

Python

# Python program to check and print  
# Neon Numbers upto 10000 
  
# function to check Neon Number 
def checkNeon (x) : 
    # storing the square of x 
    sq = x * x 
      
    # calculating the sum of sum of digits 
    # of sq 
    sum_digits = 0
    while (sq != 0) : 
        sum_digits = sum_digits + sq % 10
        sq = sq / 10
      
    return (sum_digits == x) 
  
# Driver Code 
  
i = 1
# Printing Neon Numbers upto 10000 
while i <= 10000 : 
    if (checkNeon(i)) : 
        print i, 
    i = i + 1
  
# This code is contributed by Nikita Tiwari. 

C#

// C# program to check and print 
// Neon Numbers upto 10000 
using System; 
  
class GFG  
{ 
    // function to check Neon Number 
    static bool checkNeon(int x) 
    { 
        // storing the square of x 
        int sq = x * x; 
  
        // calculating the sum of 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() 
                          
    { 
        // Printing Neon Numbers upto 10000 
        for (int i = 1; i <= 10000; i++)  
            if (checkNeon(i)) 
                Console.Write(i + " ");  
    } 
} 
  
// This code is contributed by vt_m. 

PHP

<?php 
// PHP program to check and print 
// Neon Numbers upto 10000 
  
function checkNeon($x) 
{ 
      
    // storing the square of x 
    $sq = $x * $x; 
  
    // calculating the sum of  
    // sum of digits of sq 
    $sum_digits = 0; 
    while ($sq != 0)  
    { 
        $sum_digits = $sum_digits +  
                         $sq % 10; 
        $sq = $sq / 10; 
    } 
    return ($sum_digits == $x); 
} 
  
    // Driver Code 
    // Printing Neon Numbers 
    // upto 10000 
    for ($i = 1; $i <= 10000; $i++)  
        if (checkNeon($i)) 
            echo $i . " ";  
              
// This code is contributed by Sam007 
?> 

Output:

1 9

This article is contributed by Nikita Tiwari. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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My Personal Notes

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

C++

Java

Python

C#

PHP

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