Ray Tracing in One Weekend is a classic course which I saw everywhere when I started learning graphics. I read it twice and learned a lot from it, but found a bunch of drawbacks from the implementation in C++:

• There's a focus on code design and splitting the code into classes that makes it harder to understand, as well as going off on Cpp-esque tangents like shared pointers.
• There's low-value components like an "interval" class that make the code much more complex than necessary.
• If you follow the design of the code (with significant boilerplate) it can make the code a lot harder to debug and box you into following the book's code conventions, which can lead to missing skills you learn by implementing it from scratch.

Run with rm -rf test.ppm && gcc main.c -lm && ./a.out > test.ppm

Final scene from Ray Tracing in One Weekend:

More samples:

With dielectrics:

Dielectrics with more samples: