Why use QVector(Qt) instead of std::vector

I'm very new to C++ and Qt, but I'm very good at C#/Java.

The point is I like cross-platform, but I'm confuse with Qt. Isn't std::vector already cross-platform, doesn't Qt provide an equivalent to a non-crossplatform thing?

Also how are File and QFile different?

A link would be nice, thanks :)

This article loooks good. It compares Qt Template Library with Standard Template Library:

• QTL vs STL

Hope, you'll find it interesting seeing all the differences listed there in the article.

EDIT:

Here is what I find interesting:

My opinion is that the biggest advantage of the QTL is that it has the same implementation (including binary compatibility) on all OSes supported by Qt. Some STL implementations might be below par when it comes to performance or they might be missing functionality. Some platforms don’t even have an STL! On the other hand, the STL is more customizable and is available in its entirety in header files… Like I said, there is no clear winner.

Like he said, no clear winner. But still reading the article makes lots of things clear. Its better to know the difference than going for one, without knowing the other.

The QVector class is reference counted and is geared to being shared without copying. Qt provides a lot of containers that correspond to STL containers. A document that describes these with some explanation of the internals and a bit of rationale:

• Inside the Qt 4 Containers

From over here:

Qt originates from a time when C++ and the standard library were not standardized or well supported by compilers. It therefore duplicates a lot of stuff that is now in the standard library, such as containers and type information. Most significantly, they modified the C++ language to provide signals, so that Qt classes can not be used easily with non-Qt classes.

The bad experience I've had with QTL was related to QTL not raising any exceptions; this makes it harder to trace and fix critical errors. Also, STL implementations are closely related to a compiler, because parts of the library require compiler-specific extensions to the language. This means a STL implementation can often outperform QTL, which needs to be portable and therefore cannot benefit from said extensions. The debugging issue was critical for me though.