1, the constant classification and characteristics
(1) Character Constants: double quotes portion.
(2) integer constant: to write directly on the numbers, no decimal point.
(3) floating-point constants: write directly on the digital, contain a decimal point.
(4) character constants: due to a single character in single quotes (containing only one character)
(5) Boolean constants: true, flase (containing only these two values)
(6) empty constants: null (means no data)
2 Notes constants printout
(1) between the double-quoted string may be empty.
(2) can not be empty between the single quote character.
Note: between the single quote character can be a space, but can not write more characters in a row, only to write one.
(3) Air Constant not be directly used to print output.
3, for example Code
(1) source
(2) Run results
