A prime is a positive integer p having exactly two positive divisors, namely 1 and p. An integer n is composite if n > 1 and n is not prime. (The number 1 is considered neither prime nor composite.)

We can frame a brute force algorithm for checking primality of numbers using the above statement.

bool is_prime(int number) {
    int factor = 0;
    for (int i = 0; i <= number; ++i) {
        if (number % i == 0) {
            factor++;
        }
    }
    return (factor == 2)? true : false;
}

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