automatic international prefix?

To dial a Hong Kong number manually requires adding prefix:

011-852-1234-5678
where
011 is an international phone call prefix
852 is Hong Kong's country code
1234-5678 is a local Hong Kong phone #

If I store this number in my google phone (a galaxy nexus), should I store all the numbers including the prefix and country code?

If I do that, and then I travel to Hong Kong and buy a local sim card, do I then have to manually edit all these phone numbers to remove the 011 852 prefixes, and add 011 1 prefixes to all my USA phone numbers? There should be an easier solution.