/*HELLO EVERYONE IT'S A SIMPLE PRIME NUMBER CALCULATOR WHICH CAN SAVE PRIMES IN .TXT FILES. It counts prime numbers up to 18.446.744.073.709.551.615 CREATED BY ME - https://www.sololearn.com/Profile/618881 */ #include #include #include using namespace std; int main() { // some int's and long int's here int primeCounter = 0; unsigned long long begin_number; unsigned long long end_number; unsigned long long counts_primes = 1; // "main menu" cout << "The first number to check:"; cin >> begin_number; cout << "\nThe Last number to check:"; cin >> end_number; system("cls"); // cout for 0,1,2 bcz iteration starts on 2 /*cout << "0 is not a prime number!\n"; cout << "\n1 is not a prime number!\n"; cout << "\n2 is a prime number!\n";*/ ofstream myfile; myfile.open ("primes.txt"); //logic while(begin_number != end_number) { if(primeCounter > 0) primeCounter = 0; // unbugging the 2 if (begin_number == 2) { cout << "\n"<< begin_number << " - the " << counts_primes << " prime" << endl; myfile << "\n"<< begin_number << " - the " << counts_primes << " prime" << endl; } for (unsigned long long i = 2 ; i < begin_number ; i++ ) { if(begin_number % 2 == 0) { break; } if(begin_number % i == 0) { //Sleep(100); cout << begin_number << " is not because it can be divided by "<< i << endl; primeCounter++; if(primeCounter > 0) break; } if (i == begin_number - 1 && primeCounter == 0) { counts_primes++; cout << "\n"<< begin_number << " - the " << counts_primes << " prime" << endl; myfile << "\n"<< begin_number << " - the " << counts_primes << " prime" << endl; } } begin_number++; } cout << "you've found " << counts_primes << " prime numbers!" << endl; myfile.close(); system("pause"); return 0; }

Simple prime number calculator with .txt saving option