Q1.What is Pre & Postsolution in .NET ?
never heard about it
its the visual studio solution user option file, it is used to store IDE user customised IDE settings, it also holds some sourcesafe information.
Q3.What is the current ranking of programming languages(in terms of their
scope,demand) ? C,C++,JAVA,.NET etc
Demand for C is in embedded platform.
C++ is in driver development (both win as well as in *nix as well as in BSD ) and also application programming in linux via QT/GTK , Win32 Programming in windows. And basically not for web development. This is baap of all programming languages very powerfull but people go away from it as the learning curve is a bit steep.
Java , used to build web applications, applets/apps, and also apps for mobile devices. One language for many platform.
.NET - is also used for building web applications, win apps , as well as mobile device application. Many languages for one platform. The major programming language is C# and vb.net J#( similar to java), but .NET also support about 25+ other languages. what this does is it gives you the freedom to chose you programming language of your choice.
The demand is everywhere, be it C,C++, java or .NET . Job openings of skilled C/C++ developers is low considering java and .NET , when it comes to java & .NET both are same. there are thousands of companies offering jobs in these two fields.