Hello, I want to know, when we should use int, const int or define I have seen some codes and I'm not sure when to use each of them when you define a pin output or input int ledPin = 13; // the number of the LED pin const int ledPin = 13; // the number of the LED pin #define ledPin 13 // the num…

#define takes no actual RAM, any other "int" like definition does. If you were planning to use "const", then #define will probably work.

You use "int" if you want to store a value between -32768 and 32767 that you want to be able to change. This uses 2 bytes of RAM. You use "const int" if you want to reference a value by name - you use it just like any ordinary int, but you cannot change the value. This does not use any RAM. The val…

Thanks a lot for the answers, I have a much more clear panorama now. And now that we see that one of the advantages is to "save RAM" I have one question, that I think it's related with this. If I use const int ThisIsTheLedOnTheRightColorRed = 10; will that take more bytes than something like co…

The number of characters in a variable name will have no impact on the size of your program or its use of RAM.

It should be mentioned, that #define is a preprocessor operator, doing text replacement. #define PI 3.141 will not define a variable, it just replaces every time where PI is found in the source code with 3.141. And there can be the problem, if you write #define PI 3.141o it is fine until the compile…

When to use int, const int or define

Projects Programming

KeithRB April 5, 2013, 3:46pm 2

The only one not to use is the naked int. This uses up precious RAM space.

const int or #define should be fine.

Topic		Replies	Views
What is the difference between int ledPin and #define ledPin Programming	48	591	June 10, 2025
Use of expression in #define directive Programming	57	492	April 18, 2026
const int / int Programming	19	101787	May 5, 2021
What the difference? #define vs static global variable Programming	30	505	October 2, 2025
When to use const int, int, or #define Programming	14	48046	May 6, 2021

When to use int, const int or define

Related topics