using static System.Console;

using System.Collections.Generic;

​

using System;

​

public class Program {

    public static void Main() {

        WriteLine(typeof(Nullable).Name);

        WriteLine(typeof(Nullable<>).Name);

        int? nInt = 0;

        decimal? nDecimal = 0M;

        List<int> lInt = new List<int>();

        int xInt = 1;

        string xString = "";

        decimal xDecimal = 2M;

        Dictionary<string, int> dStingInt = new Dictionary<string, int>();

        PrintObject<int?>(nInt);

        PrintObject<decimal?>(nDecimal);

        PrintObject<List<int>>(lInt);

        PrintObject<int>(xInt);

        PrintObject<string>(xString);

        PrintObject<decimal>(xDecimal);

        PrintObject<Dictionary<string, int>>(dStingInt);

    }

    private static void PrintObject<T>(T obj) {

        var type = typeof(T); 

        var generic = type.IsGenericType;

        var nullable = generic && type.GetGenericTypeDefinition() == typeof(Nullable<>);

        WriteLine($"{type.Name} - {type.IsGenericType} - {(generic ? type.GetGenericTypeDefinition().Name : (""))} - {(nullable ? Nullable.GetUnderlyingType(type).Name : (""))} - {type.Name}\n");

    }

}