Define a linked list of a linked list
Eric Sheppard
ce1zzes at prism.gatech.EDU
Wed Sep 19 10:19:02 AEST 1990
I've just given myself a crash course in C, to bring myself up to speed. My
first project, a FORTRAN to C program conversion, was a resounding success.
The resulting program uses linked structures for dynamic data input; no more
hard-coded arrays! Makes the new program much more efficient and flexible.
My next project is to convert another one of my old FORTRAN programs, but this
one seems a bit more difficult.
The problem: I'm not quite sure how to handle a linked list of a linked list.
Structure : First member 4 char header, successive members 6 char data and
1 char flag.
aaaa
bbbbbb c
bbbbbb c
...
bbbbbb c Number of successive members must be variable; best way to
implement this is with a linked list.
I will be building a file of structures of the above format, and need to
manipulate and organize them, preferably in memory; a kind of database.
Depending on how efficiently the structures can be organized, I shouldn't have
to worry about running out of memory (small-scale database running on
mainframe). Since the total number of linked lists is not fixed, how can a
linked list of the above linked list be defined?
One idea: Place the header and next-structure-pointer into the outer list,
and the successive members into the inner list.
struct inner {
char data[7];
char flag;
struct inner *next;
};
typedef struct inner INNR;
typedef INNR *PT_INNR;
struct outer {
char header[5];
struct INNR; <- not sure about this declaration. Use pointer?
struct outer *next;
};
typedef struct outer OUTR;
typedef OUTR *PT_OUTR;
Are there any dangers involved with this setup? Advice would be appreciated...
Eric, tinkerer-at-large
More information about the Comp.lang.c
mailing list