path: root / Sem. 04 / example01_with_functions.cpp


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#include <iostream>
using namespace std;

bool isPrime(unsigned n)
{
	if(n <= 1)
		return false;

	double temp = sqrt(n);

	for (int i = 2; i <= temp; i++)
	{
		if (n % i == 0)
			return false;
	}

	return true;
}

int main()
{
	int n;
	cin >> n;

	for (int i = 6; i < n; i += 6)
	{
		if (isPrime(i - 1) && isPrime(i + 1))
			cout << i - 1 << " " << i + 1 << endl;
	}
}