csharp

public class A { private static int countA = 0; protected int x; public A() { countA++; this.x = 0; } public A(int x) { countA++; this.x = x; } public override string ToString() { return "A:" + this.x; } public virtual int DoIt(int z) {

return this.x * z; } public static int GetCount() { return countA; } }// end of class A

public class B : A { protected int y; private static int countB = 0; public B(int y) { this.y = y; countB++; } public B(int x, int y):base(x) {

countB++;

this.y = y; } public override string ToString() {

return "B:" + base.ToString() + ":" + this.y; } public static new int GetCount() { return countB; } public override int DoIt(int z) { return base.DoIt(z) + this.y; } } //end of class B

public class C : B { private A myA; private static int countC = 0; public C(int x, int y):base(x,y) { this.myA = new A(x + y); countC++; } public static new int GetCount() { return countC; } public override string ToString() { return "C:" + base.ToString() + " [" + this.myA + "]"; } }// end of class C