Trailing stop function based on the indicator iCA-i

A trailing stop that follows the indicator i-CAi. When price touches this indicator, all trades are closed. If and when you change the period  of the chart that the expert advisor was set in, the trailing function should not change. 

This is a fairly simple indicator, but i would like the finished product to be very customer friendly. When the trailing function begins, there should be messages in green in the lower right quadrant of the chart showing the setting of stop loss and all consequent

changes to the stop loss. I am well aware that these messages may be seen in the journal of metatrader, but i want them in small print on screen. 

 Programs should not contain critical errors that lead to immediate termination:

division by zero

going beyond array boundary

using an incorrect object pointer

Start your program on a chart and try to change the time frame or symbol. Restart the terminal with an indicator/Expert Advisor attached to it. Such actions should not lead to program errors.

Not enough history data or vice versa too many bars on the chart should not hinder the client terminal operation or cause excessive use of computer resources.