Interview questions part 2

Hi,
guys,
toady i had face a interview for the post of iPhone developer...following question were asked while interviewing me.
1) What is delegate?
2)what is the use of @synthesize?
3)what is retain and release?
4)what is the differance beetween pass by value and pass by reference?
5)Few question on my iphone project..
6)What is navigation controller?
7)getter and setter method?
8)what is @synchronize?
9)what is free and alloc?
ask some example on this.
10)what is deep copy and shallow copy?
11)function of section,row and row at index?
12)what will be output if section=2 and row=4?
13)how to run audio and video in iphone?which framework is used for this?
14)function overloading and overriding?
15)what is class?difference beetween class and structure?
16)Write a program, if u have two classes A and B. A contain some class and instance method and you have to invoke this method in B.
Do it without using inheritance?
17)How many touches events are there? explain it?
18)[class obj]
[obj retain]
[obj retain]
[obj release]
dealloc
{
}
what is the retain count?
and when dealloc will be called?

and finally i cracked this interview and got selected.
BEST luck