Program.cs

using System;

namespace Generics
{
    // Ref: https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/types/generics
    class Program
    {
        // Declare the generic class.
        public class GenericList<T>
        {
            public void Add(T input) { }
        }

        private class ExampleClass { }

        static void Main(string[] args)
        {
            // Declare a list of type int.
            GenericList<int> list1 = new GenericList<int>();
            list1.Add(1);

            // Declare a list of type string.
            GenericList<string> list2 = new GenericList<string>();
            list2.Add("");

            // Declare a list of type ExampleClass.
            GenericList<ExampleClass> list3 = new GenericList<ExampleClass>();
            list3.Add(new ExampleClass());
        }
    }
}