Exercise $7\mathrm{.}2-$ Extract domain name

Define a function to extract the domain name from an email address.

Domain name is the part after @ sign.

Write test code to ask user for an email and print out the domain name

Sample output:

Enter an email address$($ enter exit to quit$)$ : john

Domain is: Domain not found

Enter an email address$($ enter exit to quit$)$ :

john.smith@missioncollege.edu

Domain is:

missioncollege.edu

Enter an email address$($enter exit to quit$)$ :

jane.smith@sjsu.edu

Domain is:

sjsu.edu

Enter an email address$($ enter exit to quit$)$ : exit