What language does Arduino IDE use?

 The Arduino IDE primarily uses C++, but with a simplified style that often looks like a hybrid of C and C++.

Here's a detailed breakdown:

Core Language: C++

Arduino sketches are fundamentally C++ programs, but they hide some of the complexity:

• C++ Classes: The Arduino core library is written in C++ classes (like String, Serial, etc.)

• Object-Oriented Features: You can use classes, inheritance, and other OOP features

• C++ Standard Library: You can include and use C++ standard headers

What Makes It Look Different

1. Simplified Structure

Arduino hides the main function and provides two primary functions:

cpp

void setup() {
    // Runs once at startup
}

void loop() {
    // Runs repeatedly
}

Behind the scenes, this gets translated to proper C++:

cpp

#include <Arduino.h>

void setup();
void loop();

int main() {
    setup();
    while(1) {
        loop();
    }
}

2. Automatic Includes

The IDE automatically includes the Arduino core library, so you don't need to write #include <Arduino.h> in every sketch (though it's there implicitly).

3. Simplified Function Names

The API uses beginner-friendly function names:

cpp

pinMode(13, OUTPUT);        // Instead of more complex HAL functions
digitalWrite(13, HIGH);     // Simple, readable syntax
delay(1000);                // Easy-to-understand timing

Language Features You Can Use

C Subset (all supported):

• Variables, data types

• Functions, control structures

• Arrays, pointers

• Structures, unions

C++ Features (all supported):

• Classes and objects

• Function overloading

• Templates

• References

• Constructors/destructors

• Inheritance and polymorphism

Example Showing C++ Features

cpp

// This sketch uses C++ features
class Led {
  private:
    int pin;
    
  public:
    Led(int p) : pin(p) {  // Constructor with initializer list
      pinMode(pin, OUTPUT);
    }
    
    void on() {
      digitalWrite(pin, HIGH);
    }
    
    void off() {
      digitalWrite(pin, LOW);
    }
};

// Create objects (C++ feature)
Led redLed(13);
Led greenLed(12);

void setup() {
  // Object-oriented approach
}

void loop() {
  redLed.on();
  greenLed.off();
  delay(1000);
  redLed.off();
  greenLed.on();
  delay(1000);
}

Compilation Process

When you click "Verify" or "Upload":

1. Your sketch gets wrapped with the necessary C++ boilerplate

2. The Arduino core libraries are included

3. Everything gets compiled by avr-g++ (a C++ compiler for AVR chips)

4. The resulting machine code is uploaded to the board

Key Points

• Primary Language: C++

• Style: Simplified C++ that often looks like C with Arduino-specific functions

• Flexibility: You can write pure C, simple Arduino style, or full C++ with classes

• Compiler: Uses GCC-based C++ compilers (avr-g++ for AVR boards, arm-none-eabi-g++ for ARM boards, etc.)

So while it's common to say "Arduino uses C/C++", it's most accurate to say it's C++ with a beginner-friendly wrapper that makes embedded programming more accessible.