arrays, structures, and unions

of basic data types
pointers

to them
functions

that "return" them
assignment statements

such as:

lower = 0;

upper = 300;

step = 20;

fahr = lower

C language keywords

auto

 double

int

struct
break

else 

long

switch
case

enum

register

typedof
char

extern

return

union
const

float

short

unsigned
continue

for

signed

void
default

goto

sizeof

volatile
do 

if

static

while