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# Language Reference (extended)

The Arduino language is based on C/C++ and supports all standard C constructs and some C++ features. It links against AVR Libc and allows the use of any of its functions; see its user manual for details.

## 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.

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The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.

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