static void Main(string[] args)
        {
            Dog[] dogArr = new Dog[] {
                new Dog("sharo", 3, "male"),
                new Dog("balkan", 5.5, "male"),
                new Dog("Lisa", 3.2, "female")
            };

            Cat[] catArr = new Cat[] {
                new Cat("maca", 2, "female"),
                new Cat("lara", 0.5, "female"),
                new Cat("jorko", 3.8, "male")
            };

            Tomcat[] tomcatArr = new Tomcat[] {
                new Tomcat("maca", 3),
                new Tomcat("lara", 1.5),
                new Tomcat("jorko", 2.8)
            };

            var avgDogAge =
                from dogs in dogArr
                select dogs.Age;
            Console.WriteLine("The average dog age is: {0}", Convert.ToDouble(avgDogAge.Average()));

            var avgCatAge =
                  from cats in catArr
                  select cats.Age;
            Console.WriteLine("The average cat age is: {0}", Convert.ToDouble(avgCatAge.Average()));

            var avgTomcatAge =
                 from tomcats in tomcatArr
                 select tomcats.Age;
            Console.WriteLine("The average cat age is: {0}", Convert.ToDouble(avgTomcatAge.Average()));
        }