Sigh, I think that your real problem is the lack of a solid basis. I don't want to be rude but it seems that you don't know exactly what are you doing. If you need help to iterate, print a hash or even open a file, the best advice that I can give you is: "Stop now, stop to write code for a while and read some manuals".
how can i count number of keys in hash
can you tel me how to create hash table in my code.
how can i iterate all keys in my hash
I need to to fill my hash with all keys
If you open the manual for the function keys (perldoc -f keys) you will have the answer to your first question in the fourth line. If you take a look to the faqs (perldoc perlfaq) you will see that the perlfaq4 cover "How do I process an entire hash?" and "How can I know how many entries are in a hash?"
Well... just read the manual, we can't do this for you...