So i want to know if i can compare two previos data and current data. In the forum already post just compare previous and current. I do appriciate if anyone can help me 
Yes you can.
If you are having trouble with a program please post the program that represents your best attempt and tell us in detail what it actually does and what you want it to do that is different. It will make it much easier to focus on the parts you need help with rather than wasting time on things that you can do.
...R
Simply save the 2 previous values in separate variables or in 2 levels of an array. Then you can compare any combination of the 3 values (current, previous1 and previous2)