Prime Number Detection using Loops

In the realm of programming, finding prime numbers requires efficient algorithms. One common approach is employing loops, either for or while.

A previous attempt at a PHP implementation using loops resulted in incorrect estimations. Let's delve into an alternative approach.

IsPrime Function

The provided IsPrime function offers a robust solution for prime number detection:

function isPrime($num) {
    // Handling special cases: 1 is not prime, 2 is the only even prime
    if ($num == 1) {
        return false;
    } elseif ($num == 2) {
        return true;
    }

    // Efficiently handling even numbers
    if ($num % 2 == 0) {
        return false;
    }

    // Checking odd factors up to the square root
    $ceil = ceil(sqrt($num));
    for ($i = 3; $i 
Usage Example
Utilizing this function is straightforward:
$number = 17;
if (isPrime($number)) {
    echo $number . " is a prime number.";
} else {
    echo $number . " is not a prime number.";
}
Key Features
Detects prime numbers with high accuracy
Efficiently handles special cases and even numbers
No need to calculate exponents or use division arrays