析构函数怎么使用

class Program
    {
        static void Main(string[] args)
        {
            C yu = new C();
            
        }
    }
    class A
    {
      
        public A()
        {  int a;
        a = 1; Console.WriteLine("我是A构造函数"); }
        ~A() { Console.WriteLine("调用A析构函数"); }
    }
    class B : A
    {
        private int b;
        public B()
        { b = 1; Console.WriteLine("我是基于B派生类B类B构造函数");}
        ~B() { Console.WriteLine("我是调用B析构函数"); }
    }
    class C : B { private int c;
    public C() { c = 1; Console.WriteLine("我是基于C派生类C类C构造函数"); }
        ~C() { Console.WriteLine("我是C析构函数"); }
    }

}