[Data Types] Description A byte stores an 8-bit unsigned number, from 0 to 255.
Syntax
byte var = val;
Parameters var: variable name. val: the value to assign to that variable.
[Data Types] Description A short is a 16-bit data-type.
On all Arduinos (ATMega and ARM based) a short stores a 16-bit (2-byte) value. This range of -32,768 to 32,767 (minimum value of -2^15 and a maximum value of (2^15) - 1).
Syntax
short var = val;
Parameters var: variable name. val: the value you assign to that variable.
Example Code
short ledPin = 13;
[Data Types] Description Integers are your primary data-type for number storage.
An int stores a 16-bit (2-byte) value. This range of -32,768 to 32,767
Syntax
int var = val;
Parameters var: variable name. val: the value you assign to that variable.
Example Code
int countUp = 0; //creates a variable integer called 'countUp'
void setup() {
Serial.begin(9600); // use the serial port to print the number
}
void loop() {
countUp++; //Adds 1 to the countUp int on every loop
Serial.println(countUp); // prints out the current state of countUp
delay(1000);
}[Data Types] Description Store 32 bits (4 bytes), from -2,147,483,648 to 2,147,483,647.
Syntax
long var = val;
Parameters var: variable name. val: the value assigned to the variable.
Example Code
long speedOfLight_km_s = 300000L;
[Data Types] Description Datatype for floating-point numbers, a number that has a decimal point.
Syntax
float var = val;
Parameters var: variable name. val: the value you assign to that variable.
Example Code
float myfloat;
float sensorCalbrate = 1.117;
int x;
int y;
float z;
x = 1;
y = x / 2; // y now contains 0, ints can't hold fractions
z = (float)x / 2.0; // z now contains .5 (you have to use 2.0, not 2)[Data Types] Description Double precision floating point number. doubles have 8-byte (64 bit) precision.
Syntax
double var = val;
Parameters var: variable name. val: the value to assign to that variable.
Example Code
double sensorCalbrate = 1.117;
[Data Types] Description A data type used to store a character value. Character literals are written in single quotes, like this: 'A' (for multiple characters - strings - use double quotes: "ABC").
Syntax
char var = val;
Parameters var: variable name. val: the value to assign to that variable.
Example Code
char myChar = 'A';
char myChar = 65; // both are equivalent[Data Types]
Syntax
String myName = "Nook";
String(val)
String(val, base)
String(val, decimalPlaces)
Parameters val: a variable to format as a String. Allowed data types: string, char, byte, int, long, unsigned int, unsigned long, float, double. base: (optional) the base in which to format an integral value. decimalPlaces: only if val is float or double. The desired decimal places.
Example Code All of the following are valid declarations for Strings.
String stringOne = "Hello String"; // using a constant String
String stringOne = String('a'); // converting a constant char into a String
String stringTwo = String("This is a string"); // converting a constant string into a String object
String stringOne = String(stringTwo + " with more"); // concatenating two strings
String stringOne = String(13); // using a constant integer
String stringOne = String(analogRead(0), DEC); // using an int and a base
String stringOne = String(45, HEX); // using an int and a base (hexadecimal)
String stringOne = String(255, BIN); // using an int and a base (binary)
String stringOne = String(millis(), DEC); // using a long and a base
String stringOne = String(5.698, 3); // using a float and the decimal places[Data Types] Description A bool holds one of two values, true or false. (Each bool variable occupies one byte of memory.)
Syntax
bool var = val;
Parameters var: variable name. val: the value to assign to that variable.
Example Code This code shows how to use the bool datatype.
int LEDpin = 5; // LED on pin 5
int switchPin = 13; // momentary switch on 13, other side connected to ground
bool running = false;
void setup() {
pinMode(LEDpin, OUTPUT);
pinMode(switchPin, INPUT);
digitalWrite(switchPin, HIGH); // turn on pullup resistor
}
void loop() {
if (digitalRead(switchPin) == LOW) {
// switch is pressed - pullup keeps pin high normally
delay(100); // delay to debounce switch
running = !running; // toggle running variable
digitalWrite(LEDpin, running); // indicate via LED
}
}