The article is concerned with the problem of re-counting of the indicator value in the MetaTrader 4 Client Terminal when the null bar changes. It outlines general idea of how to add to the indicator code some extra program items that allow to restore program code saved before multiple re-counting.
Are you going to write your own indicator? Perhaps you will find that what you need among indicators already embedded in the client terminal. So why to reinvent the wheel? A summary table of integrated indicators' characteristics; special features and methods of attaching indicators to a chart; building of levels; displaying of indicators on different timeframes.
What happens after you have clicked on the "Start" button? The article answers this and many other questions.