[cs13001] iostream and cmath include files

[Mikhail Nesterenko]

CSI students,

During today's lecture, I showed an example where math functions, such
as squrt(), appeared to compile without

   #include <cmath> 

directive. As it turns out Microsoft's Visual Studio implements
"iostream" include file such that it itself includes "cmath". That is,
if you use Microsoft's Visual Studio and have

   #include <iostream>

directive in your program, you implicitly include "cmath" as
well. This behavior is not a part of C++ standard, it does not work on
other platforms and you should not rely on it. That is, if you use
math functions make sure to include "cmath" include file.

Thanks,
-- 
Mikhail