add virtual methods

add interface
add pure virtual
add casts
add template example

CPlusPlus/intro/main.cpp

@@ -3,6 +3,7 @@
 #include <memory>
 #include "functions.h"
 #include "ClassA.h"
+#include "ClassB.h"
 
 using namespace std;
 
@@ -107,8 +108,37 @@ int main()
 	//}
 	//cout << "sn2 refs: " << sn2.use_count() << endl;
 
-	ClassA classA;
-	ClassA classA2 = classA;
+	//ClassA classA;
+	//ClassA classA2 = classA;
+	//ClassB classB;
+	//int n = classA.GetNumber();
+	//cout << n << endl;
+	//classB.GetNumber();
+
+	IPrintable* pPrintable = nullptr;
+	pPrintable = new ClassB();
+	//(*pPrintable).Print();
+	//pPrintable->Print(); // same line as above, but simpler
+	////ClassB* pClassB2 = (ClassB*)pPrintable; // C-Cast, CAUTION: DANGER!!!
+	//ClassB* pClassB2 = dynamic_cast<ClassB*>(pPrintable); // c++ cast for polymorhpic cast
+	//float f = 1.0f;
+	//int i = static_cast<int>(f); // c++ cast, convert one static data type into another
+	////int* nonsense = reinterpret_cast<int*>(pPrintable); // c++ cast like C-Cast, CAUTION: DANGER!!!
+	//const char csz[13] = "Hello World";
+	//char* sz = const_cast<char*>(csz);
+
+	// What's the difference?
+	//const int* cip;
+	//int const* icp;
+	//int* const ipc;
+	//const int const* cicp;
+	//const int* const cipc;
+	//int const* const icpc;
+	//const int const* const cicpc;
+
+	//delete pPrintable;
+	//pPrintable = nullptr;
+	safeDelete(pPrintable);
 
 	return 0;
 }