The first two are obvious, but the third is also legal. It works because array indexing is just sugar for pointer arithmetic, so array[2]=4 is identical in meaning to *(array+2)=4. Therefore 3[array]=27 is identical to *(3+array)=27 and so is legal. But just because you can doesn't mean you should.
> There is one other convention — sometimes we repeat a key point to emphasize it. In addition, we sometimes repeat a key point to emphasize it.
One more quote and I'll stop:
> ctime() converts its argument into local time, which will vary from GMT, depending on where you are. California, where this book was written, is eight hours behind London, and several years ahead
Well it could (and I agree with WalterBright that it should) have been disallowed. a[b] being implemented as an early stage rewrite rule expanding to *(a+b) is an uninteresting implementation detail. And I doubt it is even implemented that way in modern compilers anyway. It certainly can't be in C++ as a[b] and b[a] mean different things when [] is overloaded.
That "uninteresting implementation detail" is actually of grave importance when it comes to understanding how buffer overflow attacks work. I hate to think anyone would put C code into production without understanding this.
Agreed - I've only been programming C for 38 years but I've also never found a legitimate use. However I have used it to illustrate a point when teaching C to beginners - it looks so odd they tend to remember it.
