C++ Data Types

Data Type	Size (Arduino Uno/Nano)	Stores	Example	Use
`boolean`	1 byte	`true` or `false`	`boolean ledState = true;`	ON/OFF conditions
`bool`	1 byte	`true` or `false`	`bool buttonPressed = false;`	Same as boolean (standard C++)
`byte`	1 byte	0 to 255	`byte ledPin = 13;`	Pin numbers, small positive values
`char`	1 byte	Single character	`char grade = 'A';`	Letters and symbols
`unsigned char`	1 byte	0 to 255	`unsigned char count = 200;`	Small positive numbers
`int`	2 bytes	-32,768 to 32,767	`int sensorValue;`	Most whole numbers
`unsigned int`	2 bytes	0 to 65,535	`unsigned int rpm;`	Larger positive numbers
`word`	2 bytes	0 to 65,535	`word address = 5000;`	Same as unsigned int
`long`	4 bytes	-2,147,483,648 to 2,147,483,647	`long duration;`	Large whole numbers
`unsigned long`	4 bytes	0 to 4,294,967,295	`unsigned long previousMillis;`	Timing with `millis()`
`float`	4 bytes	Decimal numbers	`float distance = 12.5;`	Measurements with decimals
`double`	4 bytes*	Decimal numbers	`double pi = 3.14159;`	Same as float on Uno/Nano
`String`	Variable	Text strings	`String name = "Arduino";`	User messages, text
`void`	No storage	No value	`void setup()`	Functions that return nothing