Added C code for IPv4 Class detection

[deepakumarvu]

Resolves Issue #88

Description

Added C code for IPv4 Class detection

How to run

• Run using Online Compiler : https://www.onlinegdb.com/online_c_compiler

Checklist

• [x] Code compiles correctly.
• [x] Changes are tested properly.
• [x] Added the README / documentation, if necessary.
• [x] Followed the Contributing guidelines.
• [x] Resolved merge conflicts, if any.

[deepakumarvu]

@krithikvaidya Can you please review this PR?

[krithikvaidya]

Nice work!