what is static_cast in c++ code example

Example 1: static_cast c++

static_cast conversion
 C++ C++ language Expressions 
Converts between types using a combination of implicit and user-defined conversions.

Syntax
static_cast < new_type > ( expression )		
Returns a value of type new_type.

Example 2: how to static_cast

struct B { };
struct D : B { };
D d;
B& br = d;
static_cast<D&>(br); // lvalue denoting the original d object