2.3 Constants

• A long constant is written with a terminal l or L (ie. 123456789L)
• An unsigned constant is written with a terminal u or U
• The suffix ul or UL indicates unsigned long
• Floating-point constants contain a decimal point (123.4) or an exponent (1e-2) (double type unless suffixed)
• The suffix f or F indicates floating constant
• A leading 0 on an integer constant means octal
• A leading 0x on an integer constant means hexadecimal
• A character constant is an integer written as one character within single quotes (ie. 'x')
• The value of character constant is the numeric value of the characters in the machine's character set (ie '0' has the value 48 in ASCII character set
• Certain characters can be represented in character and string constants by escape sequences like \n newline
• Complete set of escape sequence:

• Character constant ' \0 ' represents the character with value zero - the null character
• A string constant/literal is a sequence of zero or more characters surrounded by double quotes. ( ie. " Hello World" )
• The internal representation of a string has a null character ' \0 ' at the end, so the physical storage required is one more than the written characters length
• An enumeration is a list of constant integer values 
• The first name in an enum has value 0, the next 1, and so on, unless explicit values are specified
• If not all values are specified, unspecified value continue progression from the last value

• Enumeration associate constant value with name, an alternative to #define with auto-value generation advantage