I use Dev 5.4.1 and so far I have not found libraries which work properly for making user-interface. Allegro or graphics.h or QT or some other libraries. For Qt I have heard that you need another IDE What about the others

Qt is definitely the best, IMHO. It is not true that you need another IDE for using Qt. But it is true that it is easier with certain IDEs that have a tighter integration with Qt. This will be true for any GUI library out there.

As far as I know, the best IDEs for working with Qt are Qt Creator, Visual Studio, and KDevelop. Qt Creator is the IDE provided by Qt, and it is a pretty good IDE. Visual Studio requires that you install a Qt plugin for it, and I think it also works for the free versions of Visual Studio (the "Express" versions). KDevelop was developed in Qt and largely for Qt development (for the Linux KDE environment), so, it is well integrated with Qt out-of-the-box.

Otherwise, it is possible to use any other IDE and do Qt stuff. However, you will need not be able to use much of the traditional things you use an IDE for, because you will have to setup the build script in qmake, build your projects through the command-line (or by setting up the custom commands in DevC++), and so on. At this point, the IDE will be little more than a text editor. This is pretty much true of any other GUI library because they are generally too big and complex and require a number of extra build-scripts and things like that.

Another option that is similar to Qt is wxWidget. And the other options are mostly tied to one particular IDE, like MFC or WinForms requires Visual Studio, VCL requires C++Builder, etc..

Also note that in general, people use a front-end / back-end approach. So, all your complicated codes can be written into a back-end library (that is not tied to the GUI elements). And then you just write the simple GUI code into a front-end that calls upon the back-end to do all the heavy lifting. In that kind of scenario, you generally don't need to use the same IDE for developing them (and people generally don't use the same IDE, sometimes not even the same programming language), i.e., you use a GUI-friendly IDE for the front-end, and a streamlined "coding-frenzy" IDE to code the back-end.