int, float, bool no Arduino

A variable is a named box that holds a value while your sketch runs, so you can store a sensor reading once and reuse it later. 📦

On Arduino you must say what kind of value a box holds. The type decides how much memory it takes and what values fit inside it.

An int stores whole numbers like counts, pin numbers, or a 0 to 1023 sensor value. It is the type you will reach for most often.

On an Uno an int holds roughly -32,768 to 32,767. Go past that and the number wraps around, which can cause sneaky bugs.

A float holds numbers with a decimal point, like 23.5 degrees from a temperature sensor. Use it when whole numbers are too coarse.

A float trades exactness for range, so values are stored approximately. Avoid it for money or precise counting; it is great for sensors.

A bool holds just true or false, perfect for a yes or no fact like whether a button is currently pressed or an LED is on.

Give each variable name a clear meaning like buttonPin or doorOpen. Future you reads code faster when names say what they hold.

First you declare a variable with its type and a name, then you can read it or change it anywhere below in the same sketch.

Declare a variable above setup to make it global and shared everywhere. Declare it inside a function and only that function can see it.

Match the type to the data: int for counts and pins, float for temperatures, bool for flags. The right choice saves memory and prevents bugs.

Which type best stores a temperature reading of 23.5 degrees?

You now pick types like a pro: int for whole numbers, float for decimals, and bool for true or false flags. Clear names keep it all readable. 🎯