Get max/min from bar range

Hello Dear coders!

Help please with this task:

I want to bulid cBot which opens positions from higs/lows getting from 60(user defined) bars range. 

• (On start) It should get collection last 60 history bars
• Calculate and draw on chart High/Low from this collection
• (On Bar/On Tick) After start - continue to "collect"(update) to this collection every new bar to calculate and draw next new (updated) high/low. Collection should be fixed size 60 bars, so when every new bar appears, then last one remove from collection/calculation

Thanks for your help, I understand that this can be quite time-consuming for you.