Check Whether a Number is Neon
A neon number is defined as a number for which the sum of the digits of its square equals the number itself. For instance, 9 is a neon number because 9² = 81 and 8 + 1 = 9. This program reads an integer, computes its square, adds the digits of the square, and checks if this sum is equal to the original number.
#include <stdio.h>
int main() {
int n, square, sum = 0, rem;
printf("Enter an integer: ");
scanf("%d", &n);
square = n * n; // Compute the square
while (square != 0) {
rem = square % 10; // Extract the last digit
sum += rem; // Add it to the sum
square /= 10; // Remove the last digit
}
if (sum == n) {
printf("%d is a neon number.\n", n);
} else {
printf("%d is not a neon number.\n", n);
}
return 0;
}Enter an integer: 9
9 is a neon number.
After computing the square, the program extracts each digit of the squared value, adds it to sum, and then checks if this sum equals the original number. If they match, the number satisfies the neon property.
