Swift Tip - Extensions

Extensions allow you to extend the functionality of an existing class, structure, enumeration, or protocol.  Here is an useful example:

extension Int {

    var isPerfectSquare:Bool {

        let sr = sqrt(Double(self))

        return ((Int(sr) * Int(sr)) == self)

    }

}

The above isPerfectSquare() function extends the Int class. You can call it to check if a number is a perfect square, like this:

        print(25.isPerfectSquare) //---true---

        print(26.isPerfectSquare) //---false---

        print(27.isPerfectSquare) //---false---

        print(36.isPerfectSquare) //---true---