Then yes, you should be able to smoke in many areas. The casino- yes (although they may have a couple of tables designated non smoking you can still smoke in the casino) There will be dedicated smoking areas but there are many. You should not have a problem finding a place to smoke. You can smoke on the balcony and in your cabin but be careful not to throw anything from the balcony as it will blow back onto the ship and could start a fire.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013