Traverse Excel Items cell wise

I have read a excel file & saved its contents in a datatable.
After this, I use for each to access the values in the columns, which is successful but I want to traverse the excel data cell by cell. So for example if I want to compare data in A2 with A1 or B3 with B2, I can do that using a loop which allows me to access data cell by cell traversing through all data in a loop.