Obviously both.

Most cities have laundromats. hostels in good locations are close to them. Otherwise you can wash your clothes by hand in the sink at the hostel and hang em off your bed. Some hostels have washer/dryer facilities

bring a sink stopper and small bottle of detergent for the sink.

Also I bring a length of thin rope (maybe 1/4 inch), to tie between my bed and the window when possible as a clothes line, which helps them air dry faster. For the most part however you can rely on laudromats. Guidebooks usually list a few places and your hostel will be loaded with pamplets and flyers for all sorts of places, including laundromats. Some hostels will also have facilities as well as offer a full service.

Since your trip is less than 2 weeks, I seriously try to avoid doing laundry. If you have to do laundry, laundromat near or washer and dryer on-site at your "mid-trip" hostel is essential. You really don’t want to spend time either watching your laundry spin or dealing with clothes that didn’t-get-quite-dry when you’ve only got about 7 days that you’re actually in Europe.

Obviously Europe is not behind the times. There are several landromats available, and some hostels have them, but I didn’t see many.

Oldlady says your going for less than 2 weeks, so why are you worrying about laundry. I travelled for a month last summer and did laundry once. Just around the 2 week mark. I think that I brought enough clothes to last 1 week.

Don’t bother bringing soap. etc. You can get it from other travellers like I did, and then keep passing it on, or buy it right in the laundromat. It should be available everywhere.