Learn C to understand how the machine actually works
C is small, old, and unforgiving, and that is the point: it teaches you what a pointer is, how memory is laid out, and what every higher-level language is hiding from you. Four months at 45 minutes a day, roughly 110 hours, ends with a real program you wrote with manual memory management. Be honest with yourself — pointers are the wall almost everyone hits. Push through it and the rest of programming gets clearer.
4 months · ~110 hours · a working C program with manual memory management
1.Harvard CS50 (the C weeks)
CS50 is the best free on-ramp to C in existence, and you only need the first portion. The course opens in C precisely because it forces you to confront memory, types, and how computers work underneath, before any higher-level language papers over it. Watch the lectures, do the C problem sets in the browser-based editor, and stop when the course transitions to Python. Audit it free on edX, or use the full open materials at cs50.harvard.edu. Do the problem sets — watching the lectures alone teaches you nothing.
Free to audit; optional verified certificate ~$219
CS50x →2.C Programming: A Modern Approach
K. N. King's book is the one serious people recommend for actually learning the language well — clearer, more complete, and far gentler than the famous K&R. Work the chapters in order and do the "Programming Projects" at the end of each; this is where pointers, arrays, strings, and dynamic memory finally click. If you would rather not buy a textbook, Beej's Guide to C is free online and excellent, though it assumes you already know another language. Either way, type and run every example.
King's book ~$60–95 new; Beej's Guide free online
C Programming: A Modern Approach →3.Build one real program by hand
Write something small but complete with no library doing the hard part for you — a dynamic array or linked list you allocate and free yourself, a simple text-file parser, a tiny shell, or a memory-pool allocator. Compile with -Wall -Wextra and run it under valgrind until there are no leaks and no invalid reads. Chasing your own segfault to its cause, and fixing it, is the moment C stops being syntax and becomes understanding. Until you have manually managed memory in a program you own, you have only read about C.
Free (GCC or Clang and Valgrind are free)
Beej's Guide to C (reference) →If this doesn't fit you
If you want the machine-level understanding C gives but you are building new software rather than maintaining old code, learn Rust instead. It teaches you the same ideas about memory and ownership but the compiler enforces them, so you get the mental model without spending your evenings hunting use-after-free bugs in a debugger. Read "The Rust Programming Language," free online. Choose C only when the existing code, the hardware, or the curriculum demands it.
Why this path
Most people who "learn C" stall at pointers because a tutorial showed them the syntax without the picture of memory underneath it. The bottleneck is not the language's size — C is tiny — it is building the mental model of addresses, the stack, and the heap. CS50 plants that model with vivid, hands-on problem sets; King's book deepens it into real fluency; and the final program forces you to manage memory yourself, where the lesson actually lands. Skip the hand-built program and you will know C facts without ever having earned the understanding the language exists to teach.