A mini project on C to create and manage contacts
Functions:
1) Addition 
2) Deletion
3) Contact Search
4) Displaying Contact Book
Addition :
- Get the input for Name, Mobile Number, Email.
 - Validate
- Check whether the Name should contains alphabets only.
 - Check whether the Mobile number should contains numbers and exactly 10 digits.
 - Email must contains @, and should have the minimum length of 5.