Believe it or not the following fact was useful to me today:

Technically, a string constant is an array of characters. The internal representation of a string has a null character ” at the end, so the physical storage required is one more than the number of characters written between the quotes.

Kernighan and Ritchie, The C Programming Language, 2nd Ed., Prentice Hall, 1988.

C coders, I feel your pain.