Question

If I remember right a C-Style conversion is nothing more than an ordered set of conversions static_cast, dynamic_cast, reinterpret_cast, static_cast...,
consider:

enum NUMBERS
{
    NUMBER_ONE,
    NUMBER_TWO
};

void Do( NUMBERS a )
{
}

int _tmain(int argc, _TCHAR* argv[])
{   

    unsigned int a = 1;
    Do( a ); //C2664
    return 0;
}

a C-Style conversion would do

Do( (NUMBERS)a );

What I would like to know is, what is the correct non C-Style conversion to be made, why?

Answer 1

The correct way would be:

static_cast<NUMBERS>(a)

Because:

8) Integer, floating-point, or enumeration type can be converted to
any enumeration type (the result is unspecified if the value of
expression, converted to the enumeration’s underlying type, is not one
of the target enumeration values)

Source: http://en.cppreference.com/w/cpp/language/static_cast

dynamic_cast does runtime checks using RTTI, so it only applies to classes with at least one virtual method.

reinterprest_cast is designed to tell the compiler to treat a specific piece of memory as some different type, without any actual runtime conversions.