can some one tell me more about the functions of an engine and do you really need one in a game?

Hi!

First you have to understand what an "Engine" is!
It is just a collection of functions to do things like drawing(Graphics Engine), or playing sound(Sound Engine) or networking(Network Engine)...
When you have a collection of functions for graphics, sound, etc. for a whole game, this is called a "Game Engine".

So, you need an "Engine" , because it''s just a collection of functions!

The Wild Wild West - Desperado!