What is C?

Learn what the C programming language is, where it’s used, and why it’s a great choice for embedded systems like the Raspberry Pi Pico.

C is one of the oldest and most widely-used programming languages.
It’s fast, powerful, and gives you direct control over the hardware — which makes it perfect for microcontrollers like the Raspberry Pi Pico.

What is C?

C is a procedural programming language developed in the early 1970s.

Key features:

• Compiled (not interpreted)
• Low-level (close to the machine, but easier than assembly)
• Portable (runs on many platforms)
• Efficient and fast
• Foundation for many modern languages (like C++, Python, and Java)

Origins of ‘C’

The name “C” comes from an earlier language called “B”, which was itself derived from the language “BCPL”. C was developed by Dennis Ritchie at Bell Labs in 1972. C was designed to be a system programming language for writing operating systems and low-level applications, but it quickly became popular for all kinds of software development. C is still widely used today, especially in embedded systems, operating systems, and performance-critical applications, and languages such as Processing, Arduino, and even Python have roots in C. C is often called the “mother of all programming languages” because it has influenced so many others. It’s a procedural language, meaning it focuses on functions and procedures to operate on data, it was later extended with object-oriented features in C++.

Where is C Used?

C is used in:

• Operating systems (Linux, Windows, macOS internals)
• Embedded systems (Arduino, Raspberry Pi Pico)
• Game engines
• Robotics
• Device drivers and firmware

Anywhere speed and control matter — you’ll likely find C.

Why Use C on the Pico?

While you can use Python (via MicroPython) on the Pico, C has some big advantages:

With C, you get full control of the hardware, faster code, and better use of memory — essential for building real-world embedded systems.

What Does C Code Look Like?

Here’s a tiny example:

#include <stdio.h>

int main() {
    printf("Hello, world!\n");
    return 0;
}

This program prints a message to the terminal. Don’t worry about the syntax yet — we’ll explain everything step-by-step in future lessons.

Notice the ‘{ }’ brackets? They define blocks of code, like functions or loops; in MicroPython, you would use indentation instead.

Also notice each line ends with a semicolon (;). This tells the compiler that the statement is complete. In Python, you don’t need semicolons.

C is a compiled language, which means you write the code, then use a compiler to turn it into machine code that the Pico can run. This is different from interpreted languages like Python, where you run the code directly.

C is a typed language, meaning you must declare the type of each variable (like int, float, char, etc.) before using it. This helps catch errors early and makes your code more efficient.

Summary

C is a powerful, efficient, and long-standing language that gives you precise control over how your programs run — ideal for working on microcontrollers like the Raspberry Pi Pico.

In the next lesson, we’ll dive into variables and data types in C so you can start writing your own logic.

Next up: Variables and Data Types

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