Topics in the www.arduino.cc C Language Reference

The C Language Reference for Arduino is at the web site above. On the present web page, you are looking at the list of commands. When you are at the web page above, you can click to get examples.

Just having the command list is very helpful as you try to learn how to program Arduino. You can copy this list into a word processor and print this list with four columns to help you remember the commands.

Most people learn C language by following examples.

1 of 3 Structure

setup()

loop()

Control Structures

if...else

for

switch case

while

do... while

break

continue

return

goto

Further Syntax

; (semicolon)

{ } (curly braces)

// (single line comment)

/* */ (multi-line comment)

#define

#include

Arithmetic Operators

= (assignment operator)

+ (addition)

- (subtraction)

* (multiplication)

/ (division)

% (modulo, the remainder when you do an integer division)

Comparison Operators

== (equal to)

!= (not equal to)

< (less than)

> (greater than)

<= (less than or equal to)

>= (greater than or equal to)

Boolean Operators

&& (and)

|| (or)

! (not)

Pointer Access Operators - advanced

* dereference operator

& reference operator

Bitwise Operators - advanced

& (bitwise and)

| (bitwise or)

^ (bitwise xor)

~ (bitwise not)

<< (bitshift left)

>> (bitshift right)

Compound Operators

++ (increment)

-- (decrement)

+= (compound addition)

-= (compound subtraction)

*= (compound multiplication)

/= (compound division)

%= (compound modulo)

&= (compound bitwise and)

|= (compound bitwise or)

2 of 3 Variables

Constants

HIGH | LOW

INPUT | OUTPUT | INPUT_PULLUP

LED_BUILTIN

true | false

integer constants

floating point constants

Data Types the common ones are bolded

void

boolean true false

char

unsigned char

byte 0 to 255

int -32,768 to 32,767

unsigned int

word

long -2,147,483,648 to 2,147,483,647 used with millis() and micros()

unsigned long

short

float

double

string - char array

String - object

array

Conversion

char()

byte()

int()

word()

long()

float()

Variable Scope & Qualifiers

variable scope

static

volatile use with interrupts

const

Utilities

sizeof()

PROGMEM

3 of 3 Functions

Digital I/O

pinMode()

digitalWrite()

digitalRead()

Analog I/O

analogReference()

analogRead()

analogWrite() - PWM, pulse width modulation

Due & Zero only

analogReadResolution()

analogWriteResolution()

Advanced I/O

tone()

noTone()

shiftOut() these two require

shiftIn() added integrated circuits

pulseIn()

Time

millis() the milliseconds since the last reset

micros() the microseconds since the last reset

delay()

delayMicroseconds()

Math

min()

max()

abs()

constrain()

map()

pow()

sqrt()

Trigonometry

sin()

cos()

tan()

Characters

isAlphaNumeric()

isAlpha()

isAscii()

isWhitespace()

isControl()

isDigit()

isGraph()

isLowerCase()

isPrintable()

isPunct()

isSpace()

isUpperCase()

isHexadecimalDigit()

Random Numbers

randomSeed()

random()

Bits and Bytes - advanced

lowByte()

highByte()

bitRead()

bitWrite()

bitSet()

bitClear()

bit()

External Interrupts - advanced

attachInterrupt() warning, John E has not gotten Due interrupts to work as of August 2017

detachInterrupt()

Interrupts - advanced

interrupts()

noInterrupts()

Communication

Serial as in Serial.println

Stream

USB (32u4 based boards and Due/Zero only)

Keyboard

Mouse