/* A lab number is a number such that the square of any of its prime divisors is still one of its divisors. For example: Input: 8 Output: true (2 is a prime divisor of 8, and 2x2=4 is also a divisor of 8) Input: 50 Output: true (5 is a prime divisor of 50, and 5x5=25 is also a divisor of 50) Write a program to check if the user input is a Lab number or not. */ #include #include // std::size_t #include // std::vector bool isPrimeNumber(const std::size_t& number); bool isLabNumber(const std::size_t& number, std::vector& dividers); int main() { using namespace std; size_t range_begin; size_t range_end; // all prime dividers that satisfy condition // number % (divider * divider) == 0 vector divisors(1); cout << "Input a range: " << endl; cin >> range_begin >> range_end; //if first number in range greater than second //just swap them if(range_begin > range_end) { swap(range_begin, range_end); } cout << "All lab numbers in: " << range_begin << " - " << range_end << endl; for(size_t i = range_begin; i <= range_end; ++i) { if(isLabNumber(i, divisors)) { cout << "Number: " << i; cout << ", Divisors: "; for(auto divisor : divisors) { cout << divisor << " "; } cout << endl; } } return 0; } bool isPrimeNumber(const std::size_t& number) { if(number == 2) { return true; } else if(number % 2 == 0) { return false; } for(std::size_t i = 2; i < number / 2; ++i) { if(number % i == 0) { return false; } } return true; } bool isLabNumber(const std::size_t& number, std::vector& divisors) { bool islab = false; divisors.clear(); for(std::size_t i = 2; i <= number; ++i) { if(isPrimeNumber(i) && number % i == 0) { if(number % (i * i) == 0) { divisors.push_back(i); islab = true; } } } return islab; }

[Assignment] Lab numbers