I just changed my OS from Windows to Ubuntu Linux and I used to program in Visual C++ but it isn't available of Ubuntu. Is there any alternative to Visual C++? Plz also tell me from where can I download it.
On Ubuntu, the easiest is simply to use GCC. gcc comes with Ubuntu, and you can very easily download g++ (the C++ port of the GCC) through the command (in the terminal) of sudo apt-get install g++. If you want an IDE (rather than just a compiler), Code::Blocks and Qt Creator are fairly popular, or Geany/Emacs/Vi if you prefer more light-weight IDE's.
That's becouse GCC is a compiler, which does nothing more than converting c++ code into an executable. for example, you could compile a file named main.cpp like this:
g++ main.cpp -o main
if you want a GUI, syntax highlighting, compiling, and all that built into one program - you want and IDE like any of the 4 I named, or Qt Creator, as NT3 mentioned.
AFAIK, the Java IDEs (NetBeans and Eclipse with the C++ plugins) are the only ones that would come anywhere near Visual Studio as a debugger front end.