If you have no engine, you might also be out of electrical power… So no way to get flaps down. (I guess they are electrically operated on Cessnas?)

A failed battery will not cause the engine to fail, and the battery will work the flaps in most cases, unless coincidentally it loses its charge.

Forced landing checklist:

Speed: attain glide speed
Field: Choose suitable field preferably in front of the aircraft.
Fault: Try establish cause of engine failure, fuel pump on (n/a for C152) change fuel tanks, magnetos, mixture, carb heat, if no go then
Flaps: as required to achieve correct approach
Finals: mixture, mags, master off, doors open