# 2.4.2 Based Literals

A based_literal is a numeric_literal expressed in a form that specifies the base explicitly.

## Syntax

```based_literal ::=
base # based_numeral [.based_numeral] # [exponent]
```

```base ::= numeral
```

```based_numeral ::=
extended_digit {[underline] extended_digit}
```

```extended_digit ::= digit | A | B | C | D | E | F
```

## Legality Rules

The base (the numeric value of the decimal numeral preceding the first #) shall be at least two and at most sixteen. The extended_digits A through F represent the digits ten through fifteen, respectively. The value of each extended_digit of a based_literal shall be less than the base.

## Static Semantics

The conventional meaning of based notation is assumed. An exponent indicates the power of the base by which the value of the based_literal without the exponent is to be multiplied to obtain the value of the based_literal with the exponent. The base and the exponent, if any, are in decimal notation.

The extended_digits A through F can be written either in lower case or in upper case, with the same meaning.

## Examples

Examples of based literals:

```2#1111_1111#  16#FF#       016#0ff#  --  integer literals of value 255
16#E#E1       2#1110_0000#           --  integer literals of value 224
16#F.FF#E+2   2#1.1111_1111_1110#E11 --  real literals of value 4095.0
```