C++ Coding Challenges

[Killerapathy]

I have been learning C++ for over a year now and I would like to ask the community for some C++ coding challenges or puzzles. My professors have given me ones such as ...

int strlen(char * sz)
{

}
note: solution only took 3 lines using (recursion)

OR

"Write a C function that multiplies an input integer by 5 and returns the result. The function must not use the multiplication operator. Optimize for speed."
I believe this one actually goes into the bits.


Anyways, I wonder if you could share some of yours in hopes of challenging others.