After this lesson, you will be able to: Understand why C is still taught in 2026, where it's used, and what learning C teaches about computers.
C is 50 years old and still runs the world: OS kernels, embedded systems, language runtimes, performance-critical code. Learning C is learning how computers actually work.
This is a free introductory lesson. No purchase required.
Operating systems: Linux kernel, BSD, Windows kernel core, macOS XNU. Embedded + IoT: microcontrollers, automotive, medical devices. Language runtimes: CPython, V8 (C++/C), Ruby MRI, the Go runtime. Performance-critical: databases (PostgreSQL, SQLite, Redis), media codecs, cryptography (OpenSSL). Hardware drivers + firmware.
Forces you to think about memory (stack vs heap, allocation). Teaches what 'pointer', 'reference', 'pass by value' really mean. Reveals what every higher-level language hides, garbage collection, runtime overhead, ABI compatibility. Many CVEs are C-related (buffer overflows, use-after-free). Knowing C makes you a better security engineer.
Save as hello.c; compile with `gcc hello.c -o hello`; run `./hello`.
#include <stdio.h>int main(int argc, char *argv[]) {printf("Hello, world!\n");return 0; // 0 means success; non-zero means failure}
Pick the cleanest answer.