C / C++ / MFC

John R. Shaw wrote:

On the other hand dynamic_cast is a must for safety, even if we did not have something similar in C.

John R. Shaw wrote:

dynamic_cast is a must for safety

// Console.cpp : Defines the entry point for the console application.
//
 
#include "stdafx.h"
#include <iostream>
 
using namespace std;
 
class NoClassesDeriveFromMe
{
public:
	void Who()
	{
		cout << "NoClassesDeriveFromMe" << endl;
	}
};
 
class BaseClass
{
public:
	void Who()
	{
		cout << "BaseClass" << endl;
	}
};
 
class DerivedClass : public BaseClass
{
public:
	void Who()
	{
		cout << "DerivedClass" << endl;
	}
};
 
int main(int arvc, char* argv[])
{
	NoClassesDeriveFromMe d;
	((DerivedClass&)d).Who();
		// Clearly a coding error but will compile. C-style casts behave like
		// a 'reinterpret_cast' in this case.
 
	static_cast<DerivedClass&>(d).Who();
		// Clearly still an error (the same error) but will not compile.
 
	return 0;
}

CodeGoose wrote:

instead of running the program it opens up another instance of visual studio. And that's it. Doesn't run the program.

class A { virtual const void printName() { cout << "class A" << endl; }
class B: public A { virtual void char printName() { cout << "class B" << endl; }
class C: public B { virtual void char printName() { cout << "class C" << endl; }

C c;
A* pa = dynamic_cast<A*>&c; // cast pointer to C to pointer to A
pa->printName(); // should print ‘class C’