i want to know what is the code written in header files.(how a functions works)
is that possible
i created my own version of sqrt function in .C
now i want to know the difference b/w my code and sqrt function code.
i want to check how efficiently i created it.
You don't need sqrt source to compare your own implementation efficiency. Just run math.h sqrt in a loop - record total calculation time.
do the same thing with your sqrt - then compare execution times. Of course all conditions should be equal, that is - run experiment on same argument values and etc. Also you can compare calculation precision.