LeapYear.swift

func isLeapYear(_ year: Int) -> Bool {
    if year % 4 != 0 {
        print("The year \(year) is not leap year because it is not evenly divisible by 4.")
        return false
    } else if year % 100 != 0  {
        print("The year \(year) is a leap year because it is divisible by 4 and not by 100.")
        return true
    } else if year % 400 == 0  {
        print("The year \(year) is a leap year because it is divisible by 400")
        return true
    } else {
        print("Even though it is divisible by 4 and divisible by 100, but also not divisible by 400; so the year \(year) is not a leap year.")
        return false
    }
}

func isLeapYear(_ year: Int) -> Bool {
    let formatter = DateFormatter()
    formatter.dateFormat = "dd-MM-yyyy"
    
    let dateString = "29-02-\(String(year))"
    guard formatter.date(from: dateString) != nil else {
        return false
    }
    
    return true
}