@acer 

Hi acer 22486,
Thank you for your quick reply. My problem is actually little different, where in, I am writing a procedure that does several intermediary steps and then returns a single output (instead of the function 'f' in my func). i.e., I actually do not have any function like 'f' defined in my proc. 
The idea is to treat everything in my proc as a function that gives a single output and then apply secant method to see it's root. Please look into the following example:
 

As it can be seen, I have succesfully able to implement it based on your reply. Thanks a ton for that.

Best,
Venu

@acer 
That's exactly what I needed. Thanks a ton. 
I think I can work out the rest of it.