Improvise and remove extra code from all .cpp files

[sambhav2612]

Please help in improving the codes by removing and improvising the existing code from there appropriate places.

Please comment here so I can assign it to you on first come basis. Add yourself into CONTRIBUTORS.md under the following format:

- <Your name>[<(@Your GitHub username)>](<Your profile link>)

For example: 

- Sambhav Jain [(@sambhav2612)](https://github.com/sambhav2612)

Thanks for stopping by.

[aditya81070]

I want to envolve in this project.

[Pujolsluis]

I will work on the improvements for the bubble sort code

[sambhav2612]

@aditya81070 please commit your credentials in CONTRIBUTORS.md again

[aditya81070]

ok ,I will

[samhitav]

im interested in working on this

[sambhav2612]

@samhitav go on

[bviecelli]

I cleaned up the exe files and add a gitignore. :)