A character constant is a single character, enclosed in
single quotation marks.
e.g., ‘A’ ‘B’ ‘1’
Characters are stored internally in computer as coded set of binary
digits, which have positive decimal integer equivalents. The value of a
character constant is the numeric value of the character in the machine’s
character set. This means that the value of a character constant can vary from
one machine to the next, depending on the character set being used on the
particular machine. For example, on ASCII machine the value of ‘A’ is 65 and on
EBCDIC machine it is 193.