what is this for?

[naej]

#include <iostream>
#include <cstdlib>

i mean those

[NinjaLink]

<cstdlib>

http://www.cplusplus.com/reference/clibrary/cstdlib/

<iostream>

http://www.cplusplus.com/reference/iostream/

[necrolin]

iostream allows you to use cout, cin, etc.
cstdlib allows you to use system(), exit(), EXIT_SUCCESS, etc.

Basically, when you use the #include statement you are adding the ability to use functions/code which were previously written and are located somewhere else in your system, such as in a separate file or in a library.

[mrnutty]

iostream and cstdlib are called libraries. They contain many methods/functions that will help you from printing to screen to seeding random numbers to sorting arrays, and many more.

The #<...> is just the syntax for C++. In java the syntax is
import java.SomeLibrary. Each language has is own ways, some similar to others.