Some mind teasers

I will put some mind teasers of C++ in this thread and if you have just go on adding them.

 

We have

const A& operator=(const A& obSrc)
and
A& operator=(const A& obSrc)

What is the difference?

 

Are there any reasons one should avoid using static variables in abstract base classes?

 

How will you call a C++ function from C and Vice Versa?

 

Hi.

Code Sample

Code:

#include <iostream>
using namespace std;
class A
{
public:
    A() { throw 0; }

};

int main()
{
    try
    {
        A *pA = new A;
        delete pA;
    }
    catch (...)
    {
    }
}

Is this good code and why?

Constructor throws an exception. Now will the destructor be called ?

When is the memory allocated when a new is called? Is it after the constructor is executed or just when the constructor starts?

What happens with memory allocated for the object itself?
Who's responsible for deallocating it in such a case?

 

Is it possible to catch an assertion error?

assert (false);
catch (...) {}

 

Is it possible to implement a Singleton without using static variables or global variables.

 

Why constructors do not have return values?
What if I want to check whether the object is successfully created. We could have checked that by returning some value and finding it.

 

Write a simple template program where the .h files contains the class definition and .cpp files contains the class declaration.

 

List the operators that cannot be overloaded normally as well as friend functions?

 

What is overloading, overwriting, and overriding?

 

What you mean by virtual destructor and what are the advantages of them??

 

I always understood that in C++, if I said

a + b

a.operator+(b) is called.

Now this makes sense with the operator<< when used in the following way

cout << 100; // converts to cout.operator<<(100);

but then how does one explain this one

cout << end; // endl(cout).

In what order does C++ look for operator functions? What all functions does it search before giving up? In other words

when C++ sees

a+b

does it look for the existence of :

a.operator(b)
b(a)
a(b) ....???

or is the operator<< a special case?

 

Is there any function(s) which cannot be overloaded?

 

Should a Singleton class have a destructor and if it has what is the purpose of it?

 

I had the plans of putting the questions only but if you wish to post the answers quote the message and put them as a post to the thread as well.

There is always an option of searching within the thread so that wont be a probs.