


Description 



Interval: A regular distance or space between values. The set of points between two numbers. 
There are mainly three types of intervals:
Open interval: The interval with endpoints not included is the open interval. The open interval between two numbers a & b (a < b) is shown by (a,b).
Closed interval: The interval with endpoints included is the closed interval. The closed interval between two numbers a & b (a < b) is shown by [a,b].
Halfopen interval: The interval with one endpoint included is halfopen (halfclosed) interval. The halfopen interval between two numbers a & b (a < b) is shown either by (a,b] or [a,b) depending on which number will be included.


