What is the purpose of checkpoints in Winrunner?

Checkpoints help to compare the behavior of current application to its previous version. There are four types of checkpoints in Winrunner:

a.) Text – reads and displays the text contents of GUI objects and bit map and in bitmaps

b.) Bitmap – compares application window or area snapshots to earlier versions of the same window or area

c.) GUI – validates GUI object information (i.e. whether a button is enabled, an item is selected in a list, etc.)

d.) Database – verifies the contents and size of a set of results (based on a database query)