Code formating

[vissarion]

Is your feature request related to a problem? Please describe.
The code contains many styles since we have a few contributors now. So a code formatting tool is needed.

Describe the solution you'd like
Clang-format could be used with some well known style, e.g. google format.

[codeakki]

may I work on this issue if u guide me a little bit because I'm new here .

[vissarion]

@codeakki you are welcome to propose a PR that changes the format of a small part of library e.g. tests. Please read our contributions guide.