Introduction to C

C is the language the rest of computing is built on — small, fast, and unforgiving, it maps almost directly onto how the machine actually works.

¶What is C?

C is a compiled, statically-typed systems language created in the early 1970s.

It gives you direct control over memory and produces tiny, fast binaries — which is why operating systems, databases, and language runtimes are written in it.

¶Your first example

Here is C saying hello. Read it top to bottom — every line earns its place.

#include <stdio.h>

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

Hello, world!

¶Why learn C?

• It teaches you what is really happening under the abstractions of higher-level languages.
• It runs everywhere, from microcontrollers to supercomputers.
• Its influence is everywhere — C-family syntax shaped C++, Java, C#, Go, and more.

¶Where it is used

• Operating systems
• Embedded & firmware
• Databases & interpreters
• Performance-critical code

¶How this track works

Every topic here has four views, switchable with the tabs at the top of each page:

• Learn — the clear, practical walkthrough you are reading now.
• Deep — every detail: edge cases, the full API, and what is really happening.
• Reference — a scannable, no-fluff lookup for when you already know the shape.
• Cheatsheet — the one-page summary, printable, for quick recall.