Tools.h++ Manual

10-4 104011 Tandem Computers Incorporated
10
Here's a line-by-line description of the program:
1. Include the declarations for the class RWFileManager .
2. Struct DiskNode is a link in the linked-list. It contains:
3. The data (an int), and
4. The offset to the next link. RWoffset is typically "typedef'd" to a long
int.
5. This is the constructor for an RWFileManager . It will create a new file,
called " linklist.dat ."
6. Allocate space on the file to store the offset to the first link. This first
allocation is considered "special" and will be saved by the
RWFileManager . It can be retrieved at any time by using the member
function start() .
7. Allocate space to store the first link. The member function allocate()
returns the offset to this space. Since each DiskNode needs the offset to
the next DiskNode , space for the next link must be allocated before the
current link is written.
8. Seek to the position to write the offset to the first link. Note that the
offset to this position is returned by the member function start() .
Note also that fm has access to public member functions of class RWFile ,
since class RWFileManager is derived from class RWFile .
9. Write the offset to the first link.
10. A loop to read integers and store them in a linked-list.
11. Allocate space for the next link, storing the offset to it in the nextNode
field of this link.
12. Seek to the proper offset to store this link
13 Write this link.
fm.Write(n.nextNode);
return 0;
} // 17
Code Example 10-1