How much money do u need to survive a day in germany...except travelling and accomodation expense...answer in?

To just survive, I assume you mean 3 meals a day - nothing fancy. Plan on 5 euro each time you eat and you should be set. You can usually find sandwiches and breakfast pastries for that amount and less, but 15Euro a day would be a safe plan for food. Of course, that would not include beer, but I don't know if you consider beer essential to survive. In Germany, it almost is. ; )

if just one day then i need : one bottle of water....and 2 cheeseburgers....

Depends on what you eat, buy, and where.

For example, in Berlin:
- breakfast: anything between 50 cents (some roll) and 5 EUR (sitting in a cafe and eating some warm breakfast)
- lunch: again, anything between 1 EUR (very cheap Doenner Kebap) and some 20 EUR at some fancy restaurant
- dinner: same like the other meals.
I'd plan at least 10 EUR for meals (and be prepared to eat cheap and perhaps also bad if I do that).

Then, drinking - a bottle of water costs something like 50 cents in most supermarkets. There is a refund that you can get when you give the bottle back. Beer or cola cost slightly more.

Then, you don't want to buy anything? You don't want to go to museums? You don't want to take a guided tour (like Insider Tour), so you can fully enjoy the city? If you're only thinking about food, then you can "survive" on very little in Berlin (but Munich, Cologne or Hamburg are much miore expensive), but then you won't enjoy the tour to the fullest.

I'd say 20-30 euro would be a comfortable amount.