Structure

• void setup()
• void loop()

Control Structures

• if
• 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)

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

• * dereference operator
• & reference operator

Bitwise Operators

• & (bitwise and)
• | (bitwise or)
• ^ (bitwise xor)
• ~ (bitwise not)
• << (bitshift left)
• >> (bitshift right)
• Port Manipulation

Compound Operators

• ++ (increment)
• -- (decrement)
• += (compound addition)
• -= (compound subtraction)
• *= (compound multiplication)
• /= (compound division)
• &= (compound bitwise and)
• |= (compound bitwise or)

Variables

Constants

• HIGH | LOW
• INPUT | OUTPUT
• true | false
• integer constants
• floating point constants

Data Types

• void keyword
• boolean
• char
• unsigned char
• byte
• int
• unsigned int
• word
• long
• unsigned long
• float
• double
• string
• array

Conversion

• char()
• byte()
• int()
• word()
• long()
• float()

Variable Scope & Qualifiers

• variable scope
• static
• volatile
• const

Utilities

• sizeof() (sizeof operator)

Reference

• ASCII chart

Functions

Digital I/O

• pinMode(pin, mode)
• digitalWrite(pin, value)
• int digitalRead(pin)

Analog I/O

• AnalogReference(type)
• int AnalogRead(pin)
• AnalogWrite(pin, value) - PWM

Advanced I/O

• shiftOut(dataPin, clockPin, bitOrder, value)
• unsigned long pulseIn(pin, value)

Time

• unsigned long millis()
• unsigned long micros()
• delay(ms)
• delayMicroseconds(us)

Math

• min(x, y)
• max(x, y)
• abs(x)
• constrain(x, a, b)
• map(value, fromLow, fromHigh, toLow, toHigh)
• pow(base, exponent)
• sqrt(x)

Trigonometry

• sin(rad)
• cos(rad)
• tan(rad)

Random Numbers

• randomSeed(seed)
• long random(max)
• long random(min, max)

Bits and Bytes

• lowByte()
• highByte()
• bitRead()
• bitWrite()
• bitSet()
• bitClear()
• bit()

External Interrupts

• attachInterrupt(interrupt, function, mode)
• detachInterrupt(interrupt)

Interrupts

• interrupts()
• noInterrupts()

Communication

• Serial

Looking for something else? Try the list of community-contributed code (Web).