Documentation

Any single character enclosed in single quotes or a hexadecimal ASCII-code of a character looking like '\x10' is a character constant of integer type. Some characters like a single quote ('), double quote (") a question mark (?), a reverse slash (\), and control characters can be represented as a combination of characters starting with a reverse slash (\) according to the table below:

line feed                NL (LF)  \n
horizontal tab           HT       \t
carriage return          CR       \r
reverse slash            \        \\
single quote             '        \'
double quote             "        \"
hexadecimal ASCII-code   hh      \xhh

If a character different from those listed above follows the reverse slash, the result will not be defined:

int a = 'A';
int b = '$';
int c = '©'; // code 0xA9
int d = '\xAE';   // symbol code ®

Its internal representation is a long 4-byte integer number. Literal constants can assume values from 0 to 255. If the constant exceeds this given range, the result is undefined.