Consider the following:

class CBase
{
public:
CBase();
virtual ~CBase();

protected:
int m_protected;
};

class CDerived : public CBase
{
public:
void TestBase(const CBase& other);
void TestDerived(const CDerived& other);
};

CBase::CBase()
{
m_protected = 1;
}

CBase::~CBase()
{

}

void CDerived::TestBase(const CBase& other)
{
int fromMe = m_protected;
int fromTheOther = other.m_protected; // Error: Can't access
protected member

// declared in CBase
}

void CDerived::TestDerived(const CDerived& other)
{
int fromMe = m_protected;
int fromTheOther = other.m_protected; // No error
}

When this is compiled in MS Visual C++, the indicated error is thrown
in TestBase(), but TestDerived() does not have a problem. I would
have thought that either I'd get an error in both places or I would
not have gotten any areas. Why am I only getting one error?