public static void Main()
        {
            Cat[] cats = new Cat[]
            {
                new Cat("Jonny", 1, Sex.male),
                new Cat("Hue", 2, Sex.male),
                new Cat("Maia", 2, Sex.female),
            };

            Dog[] dogs = new Dog[]
            {
                new Dog("Ivo", 5, Sex.male),
                new Dog("Pesho", 4, Sex.male),
                new Dog("Maria", 8, Sex.female),
            };

            Frog[] frogs = new Frog[]
            {
                new Frog("Gosho", 4, Sex.male),
                new Frog("Ivan", 5, Sex.female),
                new Frog("Zahari", 3, Sex.male)
            };

            Kitten[] kittens = new Kitten[]
            {
                new Kitten("Mihaela", 5),
                new Kitten("Ivona", 3),
                new Kitten("Petra", 2)
            };

            Tomcat[] tomcats = new Tomcat[]
            {
                new Tomcat("Rado", 3),
                new Tomcat("Radoi", 3),
                new Tomcat("Frodo", 2)
            };

            Console.WriteLine("Cats average age is: ");
            Console.WriteLine("{0:F2}", Cat.AverageAge(cats));
            Console.WriteLine("The cat say: {0}", cats[0].Sound());
            Console.WriteLine();

            Console.WriteLine("Cats average age is: ");
            Console.WriteLine("{0:F2}", Dog.AverageAge(dogs));
            Console.WriteLine("The cat say: {0}", dogs[0].Sound());
            Console.WriteLine();

            Console.WriteLine("Cats average age is: ");
            Console.WriteLine("{0:F2}", Frog.AverageAge(frogs));
            Console.WriteLine("The cat say: {0}", frogs[0].Sound());
            Console.WriteLine();

            Console.WriteLine("Cats average age is: ");
            Console.WriteLine("{0:F2}", Kitten.AverageAge(kittens));
            Console.WriteLine("The cat say: {0}", kittens[0].Sound());
            Console.WriteLine();

            Console.WriteLine("Cats average age is: ");
            Console.WriteLine("{0:F2}", Tomcat.AverageAge(tomcats));
            Console.WriteLine("The cat say: {0}", tomcats[0].Sound());
        }