/****************************************** Author: Nautash Ahmad Created: 28th August, 2018 ------------------------------------------- Description: A howling prime is a prime number if the sum of its digits is also a prime number. For Example: Input:113 Output: true (113 is a prime number, 1+1+3=5 is also a prime number) Input: 89 Output: true (89 is a prime number, 8+9=17 is also a prime number) Input: 19 Output: false (19 is a prime number, but 1+9=10 is not a prime number) Write a program to check if the user input is a howling prime or not. ------------------------------------------- ******************************************/ #include using namespace std; bool PrimeCheck(int num); int BreakNumber(int num); int main() { int num1 = 0, num2 = NULL; cin >> num1 >> num2; if(num1 == 0) { cout << "Enter number greater than zero. Since zero is not a prime number"; return 0; } if(num1 && num2) { cout << "Range is from " << num1 << " to " << num2 << endl << endl; for(int i = num1; i <= num2; i++) { cout << "\n####################################\n"; cout << "Current number: " << i << endl << endl; if(PrimeCheck(i)) { int sum = BreakNumber(i); if(PrimeCheck(sum)) cout << i << " and sum of its digit(s) is " << sum << " are both prime numbers\nSo " << i << " is a Howling Prime\n"; else cout << i << " is prime but " << sum << " is not prime number\nSo " << i << " is not a Howling Prime\n"; } else cout << i << " is not a prime number \n"; cout << "####################################\n\n\n"; } } else { cout << "Entered number: " << num1 << endl << endl; if(PrimeCheck(num1)) { int sum = BreakNumber(num1); if(PrimeCheck(sum)) cout << num1 << " and sum of its digit(s) is " << sum << " are both prime numbers\nSo " << num1 << " is a Howling Prime\n"; else cout << num1 << " is prime but " << sum << " is not prime number\nSo " << num1 << " is not a Howling Prime\n"; } else cout << num1 << " is not a prime number \n"; } return 0; } bool PrimeCheck(int num) { bool isDiv = true; for(int i = 2; i <= (num / 2); i++) { if(num % i == 0) { isDiv = false; break; } } return isDiv; } int BreakNumber(int num) { int sum = 0; while(num > 0) { int rem = num % 10; sum += rem; num /= 10; } return sum; }

Howling Primes