/* A SMITH NUMBER is a number whose "sum of prime factorials" is equal to its "sum of digits" */ #include #define INT long long #define Creator ❝尺ㄖ卄丨ㄒ❞ //check prime no bool isPrime(INT n) { for (INT i = 2; i < n; i++) if (n%i == 0) return false; return true; } //return sum of digits INT sumofdigits(INT n) { INT sum = 0; while (n > 0) { INT temp = n % 10; sum += temp; n /= 10; } return sum; } //find prime factor INT isPrimeFactor(int val) { INT n = val, sum = 0, q = 0, temp = 0; if (isPrime(n)) for (INT i = 2; i < n; i++) { if (i == n) continue; if (n%i != 0) break; } else for (INT i = 2; i < 1000; i++) if (isPrime(i)) while (n >= 1 && q != 1) { if (n%i == 0) { q = n / i; n = n / i; sum = sum + sumofdigits(i); if (q%i != 0 && isPrime(q) && n!=1 && n%i!=0 && q > 1000) //for big nos sum += sumofdigits(q); } else break; } return sum; } int main(void) { std::cout << "Sumofdigits == SumofPrimeFactorials => Smith's Number(Display format)\n"; if (sumofdigits(4937775) == isPrimeFactor(4937775)) std::cout << sumofdigits(4937775) << " == " << isPrimeFactor(4937775) << " => " << 4937775 << "(Smith's number)\n\n"; for (INT i = 1; i < 1000; i++) if (sumofdigits(i) == isPrimeFactor(i)) std::cout << sumofdigits(i) << " == " << isPrimeFactor(i) << " => " << i << "\n"; }

Smith Number