Tools.h++ Manual

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17
With these rules in mind, here is a possible definition for our Bus example:
Member data busNumber_ is a C++ primitive, that is, an int . It is stored
directly using RWFile::Write(int) in the case of RWFiles , or
RWvostream::operator<<(int) in the case of virtual streams.
Member data driver_ is a RWCString . It does not inherit from
RWCollectable . It is stored using
RWvostream& operator<<(RWvostream&, const RWCString&);
Member data customers_ is a RWSet . It does inherit from RWCollectable .
It is stored using
RWvostream& operator<<(RWvostream&, const
RWCollectable&);
Finally, member data passengers_ is a little tricky. It is a pointer to an RWSet
which inherits from RWCollectable . However, there is the possibility that
the pointer is nil. If it were, then passing it to
RWvostream& operator<<(RWvostream&, const
RWCollectable&);
void Bus::saveGuts(RWFile& f) const
{
RWCollectable::saveGuts(f); // Save base class
f.Write(busNumber_); // Write primitive directly
f << driver_ << customers_; // Use Tools.h++ provided
versions
f << passengers_; // Will detect nil pointer
automatically
}
void Bus::saveGuts(RWvostream& strm) const
{
RWCollectable::saveGuts(strm); // Save base class
strm << busNumber_; // Write primitives directly
strm << driver_ << customers_; // Use Tools.h++ provided
versions
strm << passengers_; // Will detect nil pointer
automatically
}