Deconstructing "K&R C"
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Deconstructing "K&R C"
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Re: Deconstructing "K&R C"
#2This is just the first section of the chapter, right? It seems a little premature to be distributing or discussing it here.
Re: Deconstructing "K&R C"
#3This is just the first section of the chapter, right? It seems a little premature to be distributing or discussing it here.
Good point. But that's the most inspiring approach I can remember ever seeing in such a book. If only all of my technical books were written with such a mindset.
Re: Deconstructing "K&R C"
#4Isn't "assert(line != NULL && longest != NULL && "memory error");" a bug in Zed's example code?
Re: Deconstructing "K&R C"
#5Isn't "assert(line != NULL && longest != NULL && "memory error");" a bug in Zed's example code?
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Re: Deconstructing "K&R C"
#6Isn't "assert(line != NULL && longest != NULL && "memory error");" a bug in Zed's example code?
No? It ensures that malloc didn't return a NULL pointer and the '&& "memory error"' is a common pattern to add a comment describing why an assert() statement failed.
Re: Deconstructing "K&R C"
#7Isn't "assert(line != NULL && longest != NULL && "memory error");" a bug in Zed's example code?
I think you're mentally substituting "&&" with "||", in which case the assert would never fail because the string "memory error" is never 0. But with &&, the assert will fail when it should and the "memory error" is just a superfluous comment, not a bug.
Re: Deconstructing "K&R C"
#8I'm confused. What is the "defect" in K&R's "copy(char to[], char from[])" function?
The author notes that "the second this function is called...without a trailing '\0' character, then you'll hit difficult to debug errors", but no function with that signature could possibly work in this case.
The built-in "strcpy" function has the exact same limitation. Does the author have a problem with it as well? Null-termination is a fundamental concept of C strings; there's no reason to shield C students from it.
The other example of "bugs and bad style" in this "destruction" of K&R C is a minor complaint about not using an optional set of braces.
I hope the remainder of the [incomplete] chapter demonstrates some actual bugs in the book's code, because it currently doesn't live up to the first paragraph's bluster.
Re: Deconstructing "K&R C"
#9I don't see what the big deal is here. He throws inputs at a function not meant to handle them and gets a segfault. Isn't this more-or-less expected from all C functions?
On careful examination of his example code, you can see that there's no attempt to terminate the buffer (though he misidentifies it as an "off by one" error). Throwing arbitrary buffers into functions meant for null-terminate strings will cause errors everywhere, not just in K&R example code. In the next chapter, does he use strcpy in the same example and use that error to say that we should deprecate the entire standard library?
On a more nit-picky note, the 'triple-equality trick' the author derides is a common C idiom and one every C programmer should be familiar with. Perhaps it doesn't belong in the first chapter, but it definitely belongs in any C manual.
Re: Deconstructing "K&R C"
#10The greatness of the book is its terseness. Some of the code examples may be dated and buggy, but that does not diminish it at all.