On 02/27/2014 08:23 PM, Orchid Win7 v1 wrote:
> One of the most unexpected outcomes of my current employment is the
> amount of time I spend writing C++ code.
> 
> I remember I did spend a while dabbling with C++ years ago. (I think I
> even got Warp to install Haskell round about the same time...) But I
> never managed to write much beyond Hello World with it. But now, I find
> myself writing highly non-trivial code in C++. And that's kind of
> alarming, given I know nothing about C++...

I know that moment. I've also written a lot of C++ code until I realized
that I don't really _know_ the language.

I _really_ learned it when I had to give a C++ course to my colleagues.
I had (and still have) the expectation to myself to only teach what's
true. So I had to study a lot of C++'s hidden details, read the ISO
standard etc. to be sure that I tell always the truth in my course and
my pupils can rely on my words.

That reminds me on a movie quote (from "Contact"): "I had no idea!"


> For example, yesterday I wrote the following code:
> 
>   auto iter = inputs.begin();
> 
> VS happily accepted this declaration, and the code performed the way I
> had intended it to. But GCC emitted some gabled message to the effect
> that "iter" hasn't been declared or some such... Replacing the "auto"
> keyword with an explicit type signature fixed the problem. But I didn't
> think this was an especially new language feature...

You wrote C++11 code. gcc (at least up to 4.7) does C++11 code only when
requested explicitly (-std=c++11, or -std=c++0x in older compiler versions).

Don't know whether gcc 4.8 or 4.9 switch its default mode to C++11.


> Speaking of which... I think I may be fundamentally misunderstanding
> what references actually *do*. I had thought they were like pointers,

Wrong, totally wrong. Imagine C++ references just as "alias names" (to
existing objects).

Whether they might be implemented using pointers internally is not
relevant, because they just don't behave like pointers (or references in
Java) at all.

They are alias names. Nothing more.

>   std::vectpr<int> foo;
>   std::vector<int> bar;
>   std::vector<int> & baz = foo;
>   baz = bar;
>
> I had imagined that the final line changes baz from pointing to foo and
> to instead point to bar. But... if a reference can never change... then
> what the hell am I changing?? O_O

Hence "baz" is just an alias for "foo", you change "foo" if you change
"baz". That's easy, isn't it? :-)

Lars R.

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