the second edition of King's book will be released next year. should i wait until then or just get the currently available version? More on thecodingforums.com

You may not learn everything you need to optimize C programs via texts. Much of the best capability to optimize comes from understanding the architecture of the machine from a compute and memory resource standpoint. Then you can use C as a tool to write code that is optimized for CPU cycles/ time or to minimize memory resources (perhaps burning more CPU cycles). I’m Guessing you got into CPU architecture and worked in assembly and machine code some in the past. If you have that understanding, then just make sure you understand pointers and malloc/free and the compiler and linker really well. That will equip you to use C as a tool where you can structure the code to make the CPU/memory trade off More on reddit.com

Yes, the book will take time to work through. This is a good thing. There aren't really any shortcuts to learning C especially if you're a beginner. You can go with an "easier" book, but you'll be missing out on crucial information and carefully crafted exercises. You can go with a good but more terse book like the K&R book, but that assumes you already know a lot about programming. Like every time I try to work through chapter 1 or 2, all I can think about is how it’ll take 50 hrs a day and 500 days a year of work to finish it You're going to put the time in one way or the other. If you try to skip through the phase of learning to program then you're going to get stuck and you will spend that time pulling your hair out because you don't understand. This is an extremely painful and stressful way to go about it, especially if you have deadlines. Just take it one chapter or one page at a time. Don't worry about trying to absorb every single piece of information your first time through, you can tell if you're absorbing enough by how easy you find the exercises. The exercises are like self-assessment tests, they demonstrate that you did learn enough if you can complete them. Do not skip them, they're the most important part. Just keep moving and you'll get through it. More on reddit.com

If any other books are necessary to complete your studies is a question only you can answer. Probably you got enough material already and they're just a bonus. But here's my current recommendations to go to after reading King's book: "The Linux Programming Interface" by Michael Kerrisk is a gold mine of information not only about Linux and Unix, but it also provides general deeper insights about how C programs are run, what's happening in the (virtual) memory, what stack, heap, processes are all about etc. It covers multiprocessing, multithreading, network programming, and terminal programming, too. "Algorithms in C" by Robert Sedgewick - A book that's hard to get in new condition in some places, because it's old, but it's really good. It explains implementations of common algorithms in depth. Lists, stacks, trees, sorting/searching etc. Something King's book is missing or only scratching the surface of, because it focuses on describing the language itself. More on reddit.com