using System;
class A {
protected int n = 5790;
}
class B : A
{
static void Main()
{
var oa = new A();
var ob = new B();
// oa.n = 90; // error CS1540: Cannot access protected member `A.n' via a qualifier of type `A'. The qualifier must be of type `B' or derived from it
Console.WriteLine(oa);
ob.n = 10;
Console.WriteLine(ob.n);
}
}
/*
run
A
10
*/