Getting Started

Chapter 4: C Types, Operators, and Expressions

e can then use PI anywhere in our software and the compiler will automatically

erence = 0.0;

us = 0.0;

iePanRadius^2);

ecla

ent that declares to the complier how your words are

d char counter = 0’ you are telling the

mpiler that when it encounters the word ‘counter’ to consider it as data stored at

me specific location with the alias name ‘counter’ that can have values from 0

lue of 0.

algebra often enough that you need to

think they should. The compiler

than what you wanted it to do.

sion you can run into when you use the ‘=’

ssignm operator:

= y;

lay_loop_2(30000);

. The second calls the
about:

_loop_2(30000); //BAD STATEMENT

elay_loop_2(30000) function. The

’ bec use the condition, x=y, is always true, so the delay

VR compiler will think something is strange and issue

is warning:

round assignment used as truth value

W

substitute the numerical value for it:

float pieCircumf
float piePanRadi

pieCircumference = PI * (p

D rations

A declaration is a text statem
to be used. When you declare ‘unsigne
co
so
to 255, but in this case initially has a va

Arithmetic Operators.....................................................................................

Operators seem like ordinary arithmetic or algebra symbols, and they mostly are.
But they are different from arithmetic or
pay attention when operations don’t act like you
might just be doing what you told it to do, rather
An example of the kind of confu
a ent operator and the ‘==’ ‘is equal to’

x
if(x==y) _de

The first statement assigns x to the value of y
_delay_loop_2(30000) function if x is equal to y. What

if(x=y) _delay

This will set x equal to y, and then call the _d
‘if omes meaningless beca
will always run. The WinA
th

Warning: suggest parentheses a