4. It permits the method to use pointers and other constructs that might corrupt the program's memory.
5. A generic type
6. Private
7. IEnumerable<int>
8. Both ssn and name must be initialized before being passed to the method. Further, ssn must be a reference type
9. It tells the compiler that the expression _myVar refers to an instance field, even if a local variable of the same name exists.
10. Yes
11. The string that greeting points to can never be modified, but greeting can be modified to point to a different string.
12. var x = new int[]{1, 2, 3};
13. arr.Length
14. System.Int64
15. It causes a compiler warning to be issued if the method is invoked anywhere.
16.If the parameter is large, passing by reference saves data copying and can therefore by quicker.
17.The last catch block is unreachable.
18.It enforces at compile time that the class can contain only static members and types.
19. Once, after the enumeration is complete.
20. Creates a signature for the GetDensity method in the delegate class
21. +=