HP QTP : What is the difference between functions and actions in QTP

QTP Action	Function
Action is a QTP concept and it can use QTP features like own Object Repository, Data Table, checkpoints etc. Actions help make your Test modular and increase reuse. Example: You can divide your script into Actions based on functionality like Login, Logout etc. It is slow in execution.	Functions is a VB Script programming concept and do not have their own Object Repository or Data Table. Functions help in re-use of your code. Ex:  You can create a Function in your script to concatenate two strings. We can’t use checkpoints in functions, instead of checkpoints we can use validation points (Loops and Conditional statements) Functions are faster in execution than Actions