Links:

C short course lecture notes
www.tenouk.com
Struct basic  example
Anonymous  structure example
Nested  structure example
Define &  declare structure example
Define,  declare & initialize a structure example
Define,  declare & initialize a structure example 2
Bit fields  structure example
fabricating the udp, tcp, ip and other protocol  headers
How to  access structure member example
Array of  structure program example
Example  demonstrates structure containing arrays
Example  demonstrates array of structure
Let take a look  at the following program example
Structure,  function and pointers example
Structure,  function and pointer example 2
myheaderfile.c in text
main()  in text
Reactos C and C++ source code (browse the  left menu)
Linux online source code
Win32  and Windows programming
A basic use of  typedef program example
Another typedef  program example
A simple enum  program example
Another enum  program example
The  example wiith the OR operator
Consider the  following enum example
The following  program example uses enum and typedef
Union with  array and pointer example
Another  variation of the previous union example
Union, array  and pointers example: storage size
Structure,  array and pointers example: storage size
Union,  array and pointers example: structure member access
Let  change the same program to union
Let try  another example
union  initialization program example
Another  example to initialize a union
Let try a  program example: anonymous union