%
      %%       %
      %-n.m_   width n with m decimal points (floating point only)
               the optional '-' is for left-justification
               (.6 is default)
      %n       pointer to integer for # of chars written so far.
   Strings
      %c   character
      %s   string
   Decimal
      %d   integer
      %u   unsigned integer
      %o   unsigned octal
      %x   unsigned hexidecimal (abcdef)
      %X   unsigned hexidecimal (ABCDEF)
   Floating Point
      %f     float
      %e     [-]d.ddde+dd (scientific notation)
      %E     [-]d.dddE+dd
      %g/G   uses %e/%E if exponent is +/-4.  %f otherwise.
      %lf    (for scanf only, reading in double-precision numbers)
\
	\b	backspace		\f	formfeed
	\n	newline			\r	carriage return
	\t	horizontal tab		\v	vertical tab
	\\	backslash		\?	question mark
	\'	single quote		\"	double quote
	\ooo	octal			\xhh	hex number
/*	comment line(everything between ignored) */
#
	#include <headerfile.h> {include a standard library header}
	#include "headerfile.h" {include a personal header}
arithmetic
	integer division truncates decimal
	modulus equals the remainder of the integer division
assignment
	=	ex: a=0; a=b=c=0; x=5.0;
commandline
	main(int argc,char *argv[],char *eargs[])
        argc = number of command line arguments
	argv[0] = first command line argument (program pathname)
	argv[1] = second command line argument
	eargs is a collection of pointers to characters strings containing
		the session environment variables
	extern char **environ;  /* can also do the 'eargs', possibly. */
constants
	#define var 123.4	double
	#define var 123.4L	long double
	#define var 123.4F	float
	#define var 123		int
	#define var 123UL	unsigned long integer
	#define chr 'a'		character
	enum constant_expression {item1,item2,etc...};
		ex: enum boolean {NO,YES};
	const double e = 2.71828;
	const char msg[] = "warning: ";
	EOF {is} -1
Data Types
	integers
		char	character: (1 byte vax)  {ie: 'a' equals 97}
			one character in the local character set
		int	integer (4 bytes vax)
		short	short integer (2 bytes vax)
		long	long integer (4 bytes vax)
		unsigned char	ex: [0,255] (+for getting whole ascii table)
		signed char	ex: [-128,127]
	floating points
		float	single precision floating point (4 bytes vax)
		double	double-precision floating point (8 bytes vax)
	arrays
	structures
	unions
declarations
	float eps=1.0e5;	int i=5;	char c;
	char line[10];	char esc='\\';		int limit=MAX+1;
	char str1[] = "  abc";
	float v[3]; //array of 3 floats v[0],v[1],v[2]
	int a[2][5]; //two arrays of five ints
		when passing multi-dimensional arrays, acept A[][size].
		c needs to know the size of the second one.
	char* vpc[32]; //array of 32 character pointers
deliminators
	((c = getchar()) != EOF)
		{puts characters into c until EOF(-1) found}
errors
	segmentation fault
		1) pointer variable not accounted for {basically}
		2) unlocked file access
		3) accessed non-accessible memory
files
	FILE *ifp;	{ifp is a file pointer}
	ifp=fopen("file-spec","mode");	{opens a file for (read,write,or
				append) and ifp now points to that file.}
	fclose(ifp);	{closes the file pointed to by ifp}
functions
	use popen to execute a unix command and wait for completion.
	return-type function-name(parameter declarations, if any);{top of file}
	return-type function-name(parameter declarations, if any)
		{declarations;statements;}
if
	if (expr) {stmts;} else {stmts;}
	if (expr) {stmts;} else if (expr) {stmts;} else {stmts;}
	switch(expr) {case const-expr: {stmts;break;}
		      case const-expr: {stmts;break;}
		      default: {stmts;break}}
io
        gets(char *s)		/* read in s ending in \0, disregarding \n */
	fgets(char *s,MAX,FILE *stream)	/* keeps \n */
	char buf[max]; int l;	/* this set reads in an integer from
	fgets(buf,max,stdin);    * standard input, and puts it flawlessly
	sscanf(buf,"%d",&l);     * into l */
incrementing/decrementing
	++ --	pre or post decrements/increments
	+= etc.	change value(others: -=,*=,%=,/=,
jumping
	break		breaks out of the current loop
	continue	jump to the next value, repeat loop
	goto		{goto and syn nomore, o ye of little bithacking}
logical operators
	&&	(and)			||	(or)
loops
	for (i=_;until this =0{or untrue};change i) {execute block;}
	while (this is true{or non-zero}) {execute block;}
	do {stmts;} while (this is true{or non-zero});
odd header functions
	<signal.h>	sleep(unsigned int seconds) pauses for specified
			seconds
passwords
	to input a password (ie: not type on the screen), use getpass().
precedence
	Operator				Associativity
	----------				-------------
	() [] -> .				left to right
	! ~ ++ -- + - * & (type) sizeof		right to left
	* / %					left to right
	+ -					""
	<< >>					""
	< <= > >=				""
	== !=					""
	&					""
	(?)					""
	|					""
	&&					""
	||					""
	?:					""
	= += -= *= /= %= &= 94= |= <<= >>=	""
	, (discards value of left expression)	""
printf
	printf("text%dtext%ftext%c",integer,float,char);
variables
	first 31 characters significant; no reserved words; starts with letter
		or _, all others have to be either letter, digit, or _.
vt100
	general format:  (put inside quotes in a printf)
	\033{stuff}   {stuff}:  (need \033 before each of these.)
	(0_	- print graphics characters:
		_:  prints:		_:  prints:
		~~  ~~~~~~~		~~  ~~~~~~~
		a   horizontal bar	f   degree sign
		g   +/- sign		j   box low right
		k   box up right	l   box up left
		m   box low left	n   big cross-hairs
		o-s line top->bottom	t   bar right
		u   bar left		v   perpendicular
		w   1/perpendicular	x   bar
		y   less than/equal to	z   greater than/equal to
		_   blank		|   not equal to
		~   dot			`   diamond
		{   pi			}   script L
	(B	- turns graphics characters off
	[#B	- vertical tab(move down # lines)
	[#E     - line feed(# linefeeds)
	[#F [#L	- move whole screen down # lines, home cursor
	[5;3H	- screen position.  row 5, column 3.{[0;0H == [H == home}
	[J	- clear screen from positioning down
	[#M	- moves whole screen up # lines
	[#P	- delete # characters under the cursor
	[U	- home
	[U & [J - home, clear all.
	[#X	- overstrike 4 spaces starting from cursor