how i can implement variable length data base ( or data storage structure)in keil C programe?
i have another question shall we implement tree data structure in keil c51? if yes, then what size of memory required for data storage
"what size of memory required for data storage[?]"
Are you trolling? Exactly how do you expect anyone here to be able to say how much memory _you_ would need for _your_ application? Remember that you haven't told us anything about the application...
oh! sorry, i m designing C8051F020 based collage student data logger in which i m entering whole details of student (student database) & used for smart card system.
Then I would suggest something simple, like a ring buffer. Easy to throw away old entries when new data arrives and you can't read out the current log.
You will have to compute yourself your needs.
How large user ID number for each log entry? How much data for the time stamp? Depends on how long time you must be able to span, and your required resolution. How much data for additional information, such as ok/fail on PIN code entering etc.
But your project includes thinking about these kind of things. You will have to make a design. You will then have to review it. Then you will have to modify any weak spots you find. Then you implement and debug.
I think Parkinson's Law applies here...
But your project includes thinking