Many restaurants but its are expensive , the best you can do is to eat in the middle restaurant where one meal can cost 2 US§. You can find them in the heart of Algiers. If you want to eat fishes the best place is Bou haroun which is far of 15 kms from algiers , but it easy to go.
There are also many Supermarkets and several retailers where you can do your daily shopping.
All algerian food for Asean,european and american is a speciality like a couscous , Thakthoukha, Mtaouem, mechoui of lamb, etc. and many others dishes, there also many types of bread which are making by hands, .Anyway in this matter, I think that the visitor will not be desappointed.