I am implementing an API based application. As per the requirements I need to show an alert when "No Cellular Network Available".
To test reachability, use this sample code called Reachability.
To show an alert, use UIAlertView
.
Both are in Apple's documentation.
You don't have to say "you went through the documentation" or "it's urgent...". You can just ask questions! That's what Stack Overflow is for.