What coding language does Arduino use?

 The short answer is: Arduino uses a variant of C++.

But that's a bit like saying "a car uses an internal combustion engine" – it's technically correct but doesn't give you the full picture. Let's break it down in detail.

1. The Core Language: C++ with a Simplifying Wrapper

The code you write for Arduino is processed by a C++ compiler (avr-g++). However, the Arduino environment provides a simplified layer on top of standard C++.

• It's C++: You can use core C++ features like functions, variables, classes, and libraries.

• It's Simplified: The complex parts of C++ (like memory management with new/delete and the Standard Template Library - STL) are often avoided or unavailable on these small microcontrollers due to limited memory and processing power.

• It has a Unique Structure: Arduino programs are structured around two main functions, setup() and loop(), which is not standard C++ but is provided by the Arduino core libraries.

2. What It's Often Called: "The Arduino Programming Language"

Because of this specific environment and structure, many people refer to it informally as "the Arduino programming language." While not technically a new language, it's a practical way to describe the combination of C++ and the Arduino-specific libraries and functions.

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Key Characteristics of Arduino Code

Here’s what this "C++ variant" looks like in practice:

1. The Mandatory setup() and loop() Functions

Every Arduino sketch (program) must have these two functions. This is the most distinctive feature.

cpp

void setup() {
  // This code runs ONCE when the board powers up or resets.
  // Used for initialization, like setting pin modes.
  pinMode(13, OUTPUT);
}

void loop() {
  // This code runs repeatedly, over and over again, forever.
  // This is the main logic of your program.
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
  delay(1000);
}

2. Simplified, Pre-Written Functions (The Arduino API)

Arduino provides a rich set of easy-to-use functions for common tasks:

• pinMode(pin, mode) - Sets a pin as INPUT, OUTPUT, or INPUT_PULLUP.

• digitalWrite(pin, value) - Writes a HIGH or LOW value to a digital pin.

• digitalRead(pin) - Reads a HIGH or LOW value from a digital pin.

• analogRead(pin) - Reads a value from an analog pin (e.g., from a potentiometer).

• analogWrite(pin, value) - Writes a "simulated" analog value (PWM) to a pin.

• delay(ms) - Pauses the program for a specified number of milliseconds.

• Serial.begin(9600) - Starts communication with the Serial Monitor.

3. It's Mostly "Bare C++"

You use standard C/C++ syntax for everything else:

• Variables: int, float, char, byte, bool

• Control Structures: if, else, for, while, switch

• Operators: =, +, -, *, /, ==, !=, &&, ||

• Functions: You can create your own.

• Libraries: You can #include both standard C++ libraries (e.g., #include <math.h>) and user-contributed Arduino libraries (e.g., #include <Servo.h>).

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Example: Blink Sketch in "Arduino C++"

This is the "Hello, World!" of Arduino. Notice the mix of standard C++ and Arduino-specific functions.

cpp

// This is a preprocessor directive, standard in C/C++
#define LED_PIN 13

// A global variable, standard C++
int delayTime = 1000;

// The mandatory Arduino functions
void setup() {
  // Using an Arduino-specific function
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  // Using Arduino-specific functions
  digitalWrite(LED_PIN, HIGH); // Turn LED on
  delay(delayTime);            // Wait
  digitalWrite(LED_PIN, LOW);  // Turn LED off (standard C++ comment too)
  delay(delayTime);            // Wait

  // Using a standard C++ 'if' statement
  if (delayTime > 2000) {
    delayTime = 1000; // Reset the delay time
  }
}

Summary

Question	Answer
What language is an Arduino program?	A simplified version of C++.
What compiler is used?	A C++ compiler (avr-g++).
Is it a unique language?	Not officially, but it's often called one because of its specific structure and API.
Can I use standard C++?	Yes, for the most part, but you should avoid memory-intensive features.
What makes it "Arduino"?	The mandatory setup()/loop() structure and the pre-built functions like digitalWrite() and delay().

So, when you are coding for Arduino, you are essentially writing C++ code designed to be beginner-friendly and optimized for microcontrollers. This is a huge part of why Arduino has been so successful—it lowers the barrier to entry for embedded systems programming.