This actually works...

int cube::commit(const char * filename) const

{

ofstream *f = new ofstream(filename);

*f << length << endl;

f->close();

delete f;

return 0;

}

cube::cube(const char * filename)

{

ifstream *f = new ifstream(filename);

*f >> length;

f->close();

delete f;

}

int cylinder::commit(const char * filename) const

{

ofstream *f = new ofstream(filename);

*f << radius << endl;

*f << height << endl;

f->close();

delete f;

return 0;

}

cylinder::cylinder(const char * filename)

{

ifstream *f = new ifstream(filename);

*f >> radius;

*f >> height;

f->close();

delete f;

}

We write out and read back the data to and from a file.

Well, of course you have to hand-craft the “commit” function for each and every class you design.

As well as the “restore” constructor.

This can get tedious and boring after a while

and this is precisely where the OODB system comes in.

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