C++ files must be named with .cpp extension, but the site contains files named with .c extension, why is it so?
I use g++ as compiler, in which weather the file is named *.cpp or *.c does not really matter. Another main reason is I am unable to upload a file with .cpp extension into Geocities server. I advice you to down load *.c file and change extension to *.cpp.
Whats the best environment for learning C++ ?
Microsoft offers Visual Studio with a load of features, but its expensive and if you are a student in third world your pocket will be drained a lot. I prefer to use Linux, its free OS and it comes in with built in g++ compiler.
I have Windows, is there any option other than Visual Studio?
Definitely yes go to Mingw website www.mingw.org/
The use of C++ ?
C++ added a revolution to a revolution known as C. C changed the way programmers programmed. C++ gave it a object oriented dimension, this made it very easy for programmers to do their job. With C++ one can write small programs like the ones in this website or can even write a complete operating system.
What's beyond C++ ?
Java is a logical extension of C++. When it came around it was so slow and difficult to write programs that it was dismissed. Now it has come out with a bang. Java is used to program right from Embedded systems to desktop programs. Sun Java is not totally free, but C++ is.
Visual studio has excellent way to create GUI , has open source?
The workers of Microsoft have put lot of work in Visual Studio, no doubt about it. They do deserve credit. In open source one has GTK, wxWidgets, Qt and IDE's like BOA which are good to create windowed programs. Programs using GTK will feature soon on this website. But remember it runs on donations. I cant force any one to deliver. Hence it may take time.
Why not use Visual Studio ?
I don't have money enough. Though pirated versions are available, those with GPL will give you freedom to explore computing to the max.