Floating point exception: 8 on Smith number check - c++

Question

So I have written a code to check if a long int number is Smith, but I keep getting Floating point exception: 8, no matter what size do I fix my variables in. Not quite sure what I am missing.
#include <iostream>
bool isPrime(long int k) {
if (k == 1) return false;
for (long int i = 2; i*i < k; i++)
if (k % i == 0)
return false;
return true;
}
int main(){
long int n;
std::cin >> n;
long int sumPr = 0, sumCif = 0;
while (n > 0) {
sumCif += n % 10;
n = n/10;
}
for (long int i = 0; i*i<=n/2; i++) {
if (isPrime(i)) {
while (n % i == 0){
long int p = i;
while (p > 0) {
sumPr += (p % 10);
p = p/10;
}
n = n/i;
}
}
}
if (sumPr == sumCif) std::cout << "1" ; else std::cout << "0";
return 0;
}

Answer 1

The limits of this loop appear to be flawed:
for (long int i = 0; i*i<=n/2; i++) {
Possibly partly due to copy and paste from isPrime(). But the larger problem is you need to modularize this code so that you can properly test each component. And reuse modules (e.g. you implement sum of digits of a number twice in your code.) Code duplication is a potential source of error.
#include <iostream>
bool isPrime(long number) {
if (number < 2) {
return false;
}
if (number % 2 == 0) {
return (number == 2);
}
for (long divisor = 3; divisor * divisor <= number; divisor += 2) {
if (number % divisor == 0) {
return false;
}
}
return true;
}
long sum_digits(long number) {
long sum = 0;
while (number > 0) {
sum += number % 10;
number /= 10;
}
return sum;
}
long sum_prime_factor_digits(long number) {
long sum = 0;
for (long divisor = 2; divisor <= number; divisor++) {
if (isPrime(divisor)) {
while (number % divisor == 0) {
sum += sum_digits(divisor);
number /= divisor;
}
}
}
return sum;
}
bool is_smith(long number) {
if (isPrime(number)) {
return false; // only composites can play this game
}
return sum_digits(number) == sum_prime_factor_digits(number);
}
int main() {
long number;
std::cin >> number;
if (is_smith(number)) {
std::cout << "1";
} else {
std::cout << "0";
}
std::cout << "\n";
return 0;
}
TESTS
> ./a.out
4
1
> ./a.out
5
0
> ./a.out
6
0
> ./a.out
22
1
> ./a.out
4937775
1
> ./a.out
15966114
1
>
Writing clean code isn't something you do after the fact, it's what you do to help you in the debugging process.