Princess & Celebrity allow one side only on poolside deck. Some cabins are designated smoking ones.
There are various policies depends with which cruise company you are with but most are more and more are movng towards less ad less areas being available. Some don't allow smoking in your cabin but OK on the balcony, if you have one, but certainly all the dining areas are now nearly all non smoking.
You need to be a little more specific as different rules apply to different cruise lines.
If we were able to tell you by the time you get to go cruising with whichever cruise line you decide upon it could well have changed so when you are ready to go ask again. .....Neil.
On independence of the seas you can smoke port side also in disco and in a smoking room thats meant for cigar smokers but the ciggy smokers use it more if you have a balcony cabin you can also smoke on the balcony
but please if you can be more specific to which ship it helps .