In the C-Scan all the Processes are Arranged by using Some Circular List. Circular List is that in which there is no start and end point of the list means the End of the List is the Starting Point of the list. In the C-Scan Scheduling the CPU will search for the Process from Start to end and if an End has Found then this again start from the Starting Process.
Because Many Times When a CPU is executing the processes then may a user wants to enter some data means a user wants to enter Some data So that at that Situation the CPU will Again Execute that Process after the Input Operation. So that C-Scan Scheduling is used for Processing Same Processes again and Again.