Re: problem understanding :: operator in bitset class declaration
On Jan 4, 10:14 pm, swca...@gmail.com wrote:
class bitset::reference {
friend class bitset;
reference(); // no public
constructor
public:
~reference();
operator bool () const; // convert to bool
reference& operator= ( bool x ); // assign from bool
reference& operator= ( const reference& x ); // assign from bit
reference& flip(); // flip bit value
bool operator~() const; // return inverse value
}
What is the purpose of resolution operator :: in the above
declaration? Why did the creator of bitset need to introduce
other name ("reference")?
Because that's what he's definiting. There are two classes
involved here: bitset and bitset::reference. The second is a
nested class---a class that is a member of bitset. It can be
defined in one of two ways:
class bitset
{
class reference { /* definition here */ } ;
} ;
or
class bitset
{
class reference ; // forward declaration
} ;
class bitset::reference { /* definition here */ } ;
Apparently, in the above, the author has chosen the second way.
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