Should I eat something before doing weight training in the gym?!

Should I eat something before doing weight training in the gym?

If yes then what?

Should I take protein shake and my breakfast/dinner as soon as I reach home after finishing my workout or should I wait?

What’s the exact criterion?

There are many conflicting answers which I have received from different people so I am totally confused.

Please provide me with the answers.

I usually like to be hungrier when I go to the gym..especially if I'm going to do cardio because then i wont get stomach pains.
usually water holds me over...and then I eat something when I get home.

i do however eat yogurt and a peice of fruit about 30 min before I go..just so I have some energy. and i drink lots of water before and during exercise.