Private Constructors
If a class constructor is private or protected, the object cannot be created in a scope where its constructor is not visible. In the following example, Distance :: Distance ( ) is declared private.
class Distance
{
friend class CC; // a friend class
friend int Display ( ) ; // a friend function
public :
Distance ( float ) ;
// . . . .
private :
Distance ( ) ;
// . . . .
} ;
class CC
{
public :
void Compute ( )
{
Distance d1 ; // ok
}
} ;
int Display ( )
{
Distance d2 ; // ok
}
int main ( )
{
Distance d3 ; // error
// . . . .
}
Within the program, only the Distance member functions, friend class CC and friend function Display ( ) may declare Distance objects that take no argument. There is no restriction on the declaration of Distance objects that take an argument of type float.
