Virtual destructor example added.

cpp/virtual_destructor/virtual_destructor.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+
+using namespace std;
+
+class A1 {
+	public:
+		A1 () {
+			cout << "A1() called" << endl;
+		}
+
+		virtual ~A1 () { // won't be called if non-virtual
+			cout << "~A1() called" << endl;
+		}
+};
+
+class A2 : public A1 {
+	public:
+		A2 () {
+			cout << "A2() called" << endl;
+		}
+
+		~A2 () {
+			cout << "~A2() called" << endl;
+		}
+};
+
+int main (int argc, char *argv[])
+{
+	A1 *ap = new A2();
+	delete ap;
+}