C program to Check a Number is a Neon Number

Write a c program to check a number is a neon number or not using the for loop. If the number equals the sum of digits of the square of a number, it is a neon number.

1. We use the math pow function to find the square of a number.
2. Divide the output into individual digits and calculate the sum of it.
3. The if else to check whether the sum of digits in a square equals the actual number. If true, it is a neon number.

#include <stdio.h>
#include<math.h>

int main()
{
  int Number, squr, rem, Sum;
  
  printf("Enter Number to Check = ");
  scanf("%d", &Number);

  squr = pow(Number, 2);

  for (Sum = 0; squr > 0; squr = squr / 10)
  {
    rem = squr % 10;
    Sum = Sum + rem;
  }

  if (Number == Sum)
    printf("\n%d is a Neon Number.\n", Number);
  else
    printf("\n%d is not.\n", Number);
}

This C program checks whether the given number is a neon number or not using a while loop.

#include <stdio.h>
#include<math.h>

int main()
{
  int Number, squr, rem, Sum = 0;
  
  printf("Enter Number to Check = ");
  scanf("%d", &Number);

  squr = pow(Number, 2);
  printf("The Square of a Number %d = %d\n", Number, squr);

  while(squr > 0)
  {
    rem = squr % 10;
    Sum = Sum + rem;
    squr = squr / 10;
  }
  printf("The Sum of Digits in a Square = %d\n", Sum);
  if (Number == Sum)
    printf("\n%d is a Neon Number.\n", Number);
  else
    printf("\n%d is not.\n", Number);
}

Enter Number to Check = 9
The Square of a Number 9 = 81
The Sum of Digits in a Square = 9

9 is a Neon Number.

In this check neon number example, the squareDigitsSum recursive function divide and find the sum by calling it recursively.

#include <stdio.h>
#include<math.h>

int squareDigitsSum(int num)
{
  static int rem, sum = 0;

  if(num > 0)
  {
    rem = num % 10;
    sum = sum + rem;
    squareDigitsSum(num / 10);
  }
  return sum;
}

int main()
{
  int Number;
  
  printf("Enter Number to Check = ");
  scanf("%d", &Number);

  int squr = pow(Number, 2);

  int Sum = squareDigitsSum(squr);

  printf("The Square of %d Number = %d\n", Number, squr);

  printf("The Sum of Digits in %d = %d\n", squr, Sum);

  if (Number == Sum)
    printf("\n%d is a Neon Number.\n", Number);
  else
    printf("\n%d is not.\n", Number);
}

Enter Number to Check = 5
The Square of 5 Number = 25
The Sum of Digits in 25 = 7

5 is not.