CS120 - Extra Material 
------------------------ 

Read (here and in the text) and feel free to experiment with these
concepts.  However, we will not hold you responsible for them.

- pointers to functions (cool!)
	- useful for menu driven things
	- functions must be of same type & same parameter types

- unions - similar to structures, but share space, only one part at a time
	- define, declare
	- assign members, take address, access members with . and ->
	- can only initialize value of first element type in declaration
	- can access any part, but must be consistent until next part assigned

- bitfields to conserve memory, declare as int or unsigned
	struct example {
		unsigned a: 13;
		unsigned : 3; /* used as padding */
		unsigned b : 4;
	};


- #define MACRO_NAME(args) (macro expression)
	eg, #define CIRCUM(x, y) (2 * (x) + 2 * (y))
	- make sure to put args in ()
- #undef


- system calls
	system("ls");