How will you differentiate b\w two stroke engine & four stroke engines?

Answer: 2-stroke piston engine has an intake and an exhaust stroke. All air, fuel, and combustion products must be moved in those 2 strokes. A 4-stroke engine has a separate stroke for moving burned (or burning) and unburned mixtures – intake, compression, expansion, and exhaust. Using 4-stroke results in cleaner emissions at the expense of specific power.

Two stroke: For each explosion in cylinder piston moves downwards and upwards (one complete cycle) (Power stroke and Exhaust stroke).

Four stroke: for each explosion in cylinder piston moves down and upwards twice (two complete cycle) (Intake , compression, power, exhaust stroke.)

Four stroke is highly efficient than two stroke.
But two stroke is powerful than four stroke.