Everyone have to built some basic classes when learning the oop concept and even for developing database for some organization some some classes are frequently used like student class,employ class ,person class and more. My question is that why languages don't provide them on it's own ?
Besides the above, there's a point where you have to stop adding functionality to your language. There are thousands of functions and classes are that immensely more useful than your examples., but you either leave most of them out, or get humongous language implementations (e.g. Java, .NET) to accommodate all that code.
some classes are frequently used like student class
While learning C++ (and maybe other languages), you will come across classes such as "student" because that is likely to be meaningful and easy to relate-to for the person who is learning.
That is deliberate, because the emphasis is on making the C++ object correspond to a real-world object. This means the actual student of the programming language can use their knowledge and understanding of the real world and how it behaves to guide the development and understanding of the program which is written.
On a separate topic, C++ does provide the Standard Template Library (STL) in order to save application developers from having to re-invent solutions to common problems over and over again.