Why is it necessary for a base class to have a constructor that takes 0 args?

Question

This won\'t compile:

namespace Constructor0Args
{
    class Base
    {
        public Base(int x)
        {
        }
    }

    class Derived : Base
    {
    }         


        

Answer 1

This is becase when the child class is instantiated, it will also instantiate the base class. By default, it will try to find a arg less constructor. This is work with this code:

class Base
    {
        public Base(int x) { }
    }
    class Derived : Base
    {
        public Derived(int x)
            : base(x)
        {
        }
    }