A character enclosed in a pair of single quotes is a constant expression that is evaluated to the numeric code of that character in the character set that the implementation uses (e.g., ASCII, EBCDIC). For instance:

 int n = 'A'; // n = 65 on systems using ASCII 

The variable n is initialized with the numeric code of the letter A, which is 65 in ASCII. Likewise, you can obtain the numeric codes of numbers:

 int n = '9'; // n = 57

Remember not to confuse a single quote with double quotes, which indicate a string literal, not an integral value:

 char str[] = "hello world";int n = 'h'+'e'+'l'+'l'+'l'+'o'; // n equals 640