constructor_1.cs

class Base
{
    public Base()
    {
        Console.WriteLine("Base 0 constructor called");
    }
}

class Child : Base
{
    public Child()
    {
        Console.WriteLine("Child constructor called");
    }
}

class Program
{
    static void Main(string[] args)
    {
        Base c = new Child();
        Console.ReadLine();
    }
}