c++ - What is the difference between C++0x and C++11?

Question

I see mixed usage of these two terms here on SO.

Wikipedia says

C++11, also formerly known as C++0x ...

but I am not sure why.

• Why was it first called C++0x and then C++11?
• Also, what does the x stand for? My guess - like a variable?

Answer 1

C++ and C Standards are usually named after the year they are published in, which makes it easier to remember by.

For example, in C++, the original Standard was published in 1998, so we talk about C++98, and when we refer to its first correction, published in 2003, we talk about C++03.

It had been purported that the next Standard after would be done for 2008, but since it was uncertain, it was dubbed C++0x, where the x stood for either 8 or 9. In practice though, as we all know, the planning shifted and so we end-up with C++11.

Still, for the next version (C++1x), Bjarne Stroustrup stated his intent to do it in 5 years (so about 2016). For now, there are changes envisionned to the core language (concepts, modules and garbage collection), and the focus seems to be more on extending the library (filesystem for example), but it's still early so who knows!