C Questions #3

In a header file whether functions are declared or defined?
What is a far pointer? where we use it?
How will you declare an array of three function pointers where each function receives two ints and returns a float?
what is a NULL Pointer? Whether it is same as an uninitialized pointer?
What is a NULL Macro? What is the difference between a NULL Pointer and a NULL Macro?
What does the error 'Null Pointer Assignment' mean and what causes this error?
What is near, far and huge pointers? How many bytes are occupied by them?
How would you obtain segment and offset addresses from a far address of a memory location?
Are the expressions arr and &arr same for an array of integers?
Does mentioning the array name gives the base address in all the contexts?
C Important Questions

Explain one method to process an entire string as one unit?
What is the similarity between a Structure, Union and enumeration?
Can a Structure contain a Pointer to itself?
How can we check whether the contents of two structure variables are same or not?
How are Structure passing and returning implemented by the complier?
How can we read/write Structures from/to data files?
What is the difference between an enumeration and a set of pre-processor # defines?
what do the 'c' and 'v' in argc and argv stand for?
Are the variables argc and argv are local to main?
What is the maximum combined length of command line arguments including the space between adjacent arguments?
If we want that any wildcard characters in the command line arguments should be appropriately expanded, are we required to make any special provision? If yes, which?