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Stroustrup Reveals What's New In C++ 11
snydeq writes "Bjarne Stroustrup discusses the latest version of C++, which, although not a major overhaul, offers many small upgrades to appeal to different areas of development. From the interview: 'I like the way move semantics will simplify the way we return large data structures from functions and improve the performance of standard-library types, such as string and vector. People in high-performance areas will appreciate the massive increase in the power of constant expressions (constexpr). Users of the standard library (and some GUI libraries) will probably find lambda expressions the most prominent feature. Everybody will use smaller new features, such as auto (deduce a variable's type from its initializer) and the range-for loop, to simplify code.'"
Don't forget initializer lists, variadic templates, non-static data member initializers, finally fixing that Template> (note the >>) thing, rvalues, nullptr, strongly-typed enums, constructor improvements (holy god we don't have to rewrite every fucking thing every fucking time or split off into an ::init()), user-defined literals which is crazy cool combined with templates and initializer lists, and lots of stuff I'm sure I'm forgetting about.
Since starting on C#, I've kind of felt like I'm back in the dark ages in C++, even as it remains my favorite language. I've already started using a lot of these improvements, and while C++ still has it's rough edges, the improvement in "fun" while coding is massive. No more for (some_container_type<vector<map<int, string> > >::reverse_iterator aargh = instance.begin(); aargh != instance.end(); ++aargh) for me!
<xml><I><am><so><damn>Web 2.0</damn></so></am></I></xml>
You didn't anyway. You type in "int" to loop over a vector.
Only if you want to tie yourself to using a vector. Using a proper iterator costs you nothing in code space or execution time (because for a vector it optimizes down to just pointer arithmetic anyway), but means that at some future time you can replace that vector with a different data structure without having to modify the code that operates on it.
Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
> What C++ compiler are you using?
g++ 4.6 - standard in Ubuntu
Two of the features I'm waiting on are class level non-static initialisers and templated typedefs. I've heard Microsof's C++ compiler has better C++11 support but I've never tried it.
Beware that MingW has a bug so std::thread is disabled. I've heard mingw-w64 works better. You might want to also try boost::thread (same library essentially, except std::thread has move semantics).
> But C++11 describes a standard that absolutely nobody has ever got anywhere close to, so I don't imagine that there's going to be a lot of drive to adopt it.
All popular C++ compilers already implement large parts of C++11, so the chance of seeing widespread C++11 adaption in the not so distant future is pretty high. Also this wasn't really any different with C++98, which essentially no compiler supported on release and which then took a few years to gain widespread adoption.
"auto" was always implemented, since the very first version of C, it just had a different meaning - it means that variable has an "automatic storage class" (as opposed to "static storage class" etc). Because automatic was the default, it was almost always redundant, but it did have a meaning.
It actually goes way back to B, which only had a single data type - machine word. Variable declarations looked somewhat like C, but, for the lack of type, they started with the storage class instead, i.e.:
In C, we've got types, so you'd normally write "static int y" for a static local, and just "int z" for an automatic one - "auto" being implied. However, C inherited some of B's semantics as "default int" - i.e. if the declaration is clearly a variable, but it omits the type, assume that type to be "int" (i.e. machine word). So in C the above code snippet from B is actually valid, and declares x, y and z to all be ints.
Then "auto" got inherited by C++, which dropped the "default int", making auto completely redundant - you couldn't write "auto x" in C++ anymore, and in all other cases where you could use "auto", like "auto int x = 123", it was always redundant. So when they appropriated it for type inference in C++11, it was technically a breaking change - it just wasn't ever used by anyone in production code in the old way, so nobody noticed.