Comparing adjacent values in a file

Hi all,

after a fair amount of help from a couple of guys on here *tips hat to Adak* and many hours hunched over my computer I've completed a problem I was set and added extra functions in for 'fun'.

Unfortunately I look at the next problem and find myself at a loss for which function I need to use.

I have two sets of data in a file, A and B. A is essentially just a numerical marker and B is the value assigned to that marker. B fluctuates, A rises +1 every time. I have managed to extract the data from the file (line by line) and then put it in a new file of the user's choice. However the task assigned was to do this yet in the middle, find out which are the peak values. For example, 0.1, 0.3, 0.5, 0.3, 0.7, 0.1, 0.2, 0.1.

In this example 0.5, 0.7 and 0.2 are the peak values. I was hoping you guys would be able to inform me of a function (or hack of a function) that compares two adjacent values.

Thanks in advance!