What is the difference between NULL, '\0' and 0?

Question

In C, there appear to be differences between various values of zero -- NULL, NUL and 0.

I know that the ASCII character

Answer 1

One good piece which helps me when starting with C(Taken from the Expert C Programming by Linden)

The One 'l' nul and the Two 'l' null

Memorize this little rhyme to recall the correct terminology for pointers and ASCII zero:

The one "l" NUL ends an ASCII string,

The two "l" NULL points to no thing.

Apologies to Ogden Nash, but the three "l" nulll means check your spelling. 

The ASCII character with the bit pattern of zero is termed a "NUL". The special pointer value that means the pointer points nowhere is "NULL". The two terms are not interchangeable in meaning.