You can tweak the regex to match all extensions or feed it an alternation that will find only certain extensions.

# match any file extension
print map {"$_\n" if s/c:\\temp(.*?\.(?:\w|\d)+?)/$1/} split(/\s+|\@+/
+,$str);

# match only a few extensions
print map {"$_\n" if s/c:\\temp(.*?\.(?:c|xml|java|etc))/$1/} split(/\
+s+|\@+/,$str);
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I think you'd be better of using runrig's snippet at Re: Dealing with split, though.