Repeating some portion of the program either for a fixed number of times or as long as the condition is satisfied is called looping or iteration. there are three type of loop control structure in C. They are:
1. The For Loop:
2. The While Loop:
3. The Do-While Loop:
It is normal way to declare all the data items in a private section and all the function in public.In some situation, certain function required to be hidden like private data from outside call. Example: Task such as deleting an account from a customer file.