How to find user is logged in or Not in Magento

Magento is very popular e-commerce platform for web, Magento is important for both developers as well as Client. Magento has many in built function to get specific information, Here we will discuss snippet of code to identify user is logged in or not in Magento.
This tutorial help to identify magento user is logged-in or not using isLoggedIn() method.
You can also check other tutorial of magento,

Check user is logged-in or Not