Check for Prime number

[Maestro]

#include <iostream>

#include <cmath>

using namespace std;

int main()
{
	int n;

	cout<<"Enter a number: ";

	cin>>n;

	bool is_prime = true;

	if (n < 2)
	{
		is_prime = false;
	}

	else if (n == 2)
	{
		is_prime = true;
	}

	else if (n % 2 == 0)
	{
		is_prime = false;
	}

	else
	{
		for (int div = 3; div <= sqrt(n); div++)
		{
			if (n % div == 0)
			{
				is_prime = false;

				break;
			}
		}
	}

	if (is_prime == true)
	{
		cout<<"The number "<<n<<" is a prime number."<<endl;
	}

	else
	{
		cout<<"The number is not a prime number"<<endl;
	}

	return 0;
}

Is my code alright? Please help.

[kaduuk]

try testing before posting ;)

I just compiled it (compiled fine) and ran it..

Judging by the outputs it's alright :)

Cheers!

[ne555]

I think that you may have trouble with div <= sqrt(n), because of round-off errors.
Besides that it is correct, but could be faster.