Literals/Floating point

Programming languages have different ways of expressing floating-point literals.

Task

Show how floating-point literals can be expressed in your language: decimal or other bases, exponential notation, and any other special features.

You may want to include a regular expression or BNF/ABNF/EBNF defining allowable formats for your language.

Related tasks

11l

<lang 11l>// 64-bit floating point literals: 2.3 0.3e+34

// single precision (32-bit) floating point literals: 2.3s 0.3e+34s</lang>

360 Assembly

IBM hexadecimal floating point <lang 360asm>XS4 DC E'1.23456E-4' short floating-point

XDPI DC D'3.141592653589793' long floating-point XD1 DC D'0' long floating-point XD2 DC D'1' long floating-point XD3 DC D'-1' long floating-point XD4 DC D'1.2345E-4' long floating-point

XQPI DC L'3.14159265358979323846264338327950' extended

short floating-point - 32 bits - 4 bytes : 6 decimal digits
long floating-point - 64 bits - 8 bytes : 16 decimal digits
extended floating-point - 128 bits - 16 bytes : 33 decimal digits

absolute approximate range: 5e-79 to 7e75 </lang>

Real literals contain decimal point. The exponent part is optional. Underline may be used to separate groups of digits. A literal does not have sign, + or - are unary operations. Examples of real literals: <lang Ada> 3.141_592_6 1.0E-12 0.13 </lang>

Aime

<lang aime>3.14 5.0 8r # without the "r"(eal) suffix, "8" would be an integer .125</lang>

ALGOL 68

<lang algol68># floating point literals are called REAL denotations in Algol 68 #

They have the following forms: #
1: a digit sequence followed by "." followed by a digit sequence #
2: a "." followed by a digit sequence #
3: forms 1 or 2 followed by "e" followed by an optional sign #
followed by a digit sequence #
4: a digit sequence follows by "e" followed by an optional sign #
followed by a digit sequence #
#
The "e" indicates the following optionally-signed digit sequence is #
the exponent of the literal. #
If the implementation allows, a "times ten to the power symbol" #
can be used to replace "e" - e.g. a subscript "10" character #
#
spaces can appear anywhere in the denotation #
Examples: #

REAL r; r := 1.234; r := .987; r := 4.2e-9; r := .4e+23; r := 1e10; r := 3.142e-23; r := 1 234 567 . 9 e - 4; </lang>

ALGOL W

<lang algolw>begin

   real r; long real lr;
   % floating point literals have the following forms:                      %
   %    1 - a digit sequence followed by "." followed by a digit sequence   %
   %    2 - a digit sequence followed by "."                                %
   %    3 - "." followed by a digit sequence                                %
   %    4 - one of the above, followed by "'" followed by an optional sign  %
   %        folloed by a digit sequence                                     %
   % the literal can be followed by "L", indicating it is long real         %
   % the literal can be followed by "I", indicating it is imaginary         %
   % the literal can be followed by "LI" or "IL" indicating it is a long    %
   % imaginary number                                                       %
   % an integer literal ( digit sequence ) can also be used where a         %
   % floating point literal is required                                     %
   % non-imaginary examples:                                                %
   r  := 1.23;
   r  := 1.;
   r  := .9;
   r  := 1.23'5;
   r  := 1.'+4;
   r  := .9'-12;
   r  := 7;
   lr := 5.4321L;

end.</lang>

Applesoft BASIC

All numeric literals are treated as floating point. (In the Apple II world, Applesoft was sometimes called "floating-point BASIC" to contrast it with Integer BASIC.)

0
19
-3
29.59
-239.4
1E10
1.9E+09
-6.66E-32

Arturo

<lang rebol>pi: 3.14 print [pi "->" type pi]</lang>

Output:

3.14 -> :floating

AWK

With the One True Awk (nawk), all numbers are floating-point. A numeric literal consists of one or more digits '0-9', with an optional decimal point '.', followed by an optional exponent. The exponent is a letter 'E' or 'e', then an optional '+' or '-' sign, then one or more digits '0-9'.

Other implementations of Awk can differ. They might not use floating-point numbers for integers.

This Awk program will detect whether each line of input contains a valid integer.

<lang awk>/^([0-9]+(\.[0-9]*)?|\.[0-9]+)([Ee][-+]?[0-9]+)?$/ { print $0 " is a literal number." next }

{ print $0 " is not valid." }</lang>

A leading plus or minus sign (as in +23 or -14) is not part of the literal; it is a unary operator. This is easy to check if you know that exponentiation has a higher precedence than unary minus; -14 ** 2 acts like -(14 ** 2), not like (-14) ** 2.

Axe

Axe does not support floating point literals. However, it does support converting floats to integers and vice versa. <lang axe>123→float{L₁} float{L₁}→I</lang>

Axe does, however, support fixed-point literals. <lang axe>12.25→A</lang>

There are some mathematical operators in Axe that operate specifically on fixed-point numbers.

BBC BASIC

<lang bbcbasic> REM Floating-point literal syntax:

     REM  [-]{digit}[.]{digit}[E[-]{digit}]
     
     REM Examples:
     PRINT -123.456E-1
     PRINT 1000.0
     PRINT 1E-5
     
     REM Valid but non-standard examples:
     PRINT 67.
     PRINT 8.9E
     PRINT .33E-
     PRINT -.</lang>

Output:

bc

A literal floating point number can be written as .NUMBER, NUMBER. or NUMBER.NUMBER where NUMBER consists of the hexadecimal digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. If digits in the number are greater than or equal to the current value of ibase (i.e. the input number radix) the behaviour is undefined.

Examples:

12.34   .34   99.   ABC.DEF

C

Floating-point numbers can be given in decimal or hexadecimal. Decimal floating-point numbers must have at least one of a decimal point and an exponent part, which is marked by an E:

((\d*\.\d+|\d+\.)([eE][+-]?[0-9]+)?[flFL]?)|([0-9]+[eE][+-]?[0-9]+[flFL]?)

Hexadecimal is similar, but allowing A-F as well as 0-9. They have a binary exponent part marked with a P instead of a decimal exponent:

(0[xX]([0-9a-fA-F]*\.[0-9a-fA-F]+|[0-9a-fA-F]+\.)([pP][+-]?\d+[flFL]?)|(0[xX][0-9a-fA-F]+[pP][+-]?\d+[flFL]?)

C#

Floating point suffixes are not case-sensitive. <lang csharp>double d = 1; d = 1d; d = 1D; d = 1.2; //double is the default if there's no suffix d = 1.2d; //The suffix is redundant here d = .2; d = 12e-12; d = 12E-12; d = 1_234e-1_2; //digit separators are allowed since C# 7 float f = 1; f = 1f; f = 1F; f = 1.2f; f = .2f; f = 12e-12f; f = 12E-12f; f = 1_234e-1_2f; decimal m = 1; m = 1m; m = 1m; m = 1.2m; m = .2m; m = 12e-12m; m = 12E-12m; m = 1_234e-1_2m;</lang>

C++

<lang cpp>#include <iostream>

int main() {

 // a numeric literal with decimal point is a double
 auto double1 = 2.5;

 // an 'f' of 'F' suffix means the literal is a flaot 
 auto float1 = 2.5f;

 // an 'l' or 'L' suffix means a long double
 auto longdouble1 = 2.5l;

 // a number after an 'e' or 'E' is the base 10 exponent
 auto double2 = 2.5e-3;
 auto float2 = 2.5e3f;

 // a '0x' prefix means the literal is hexadecimal. the 'p' is base 2 the exponent
 auto double3 = 0x1p4;
 auto float3 = 0xbeefp-8f;

 std::cout << "\ndouble1: " << double1;
 std::cout << "\nfloat1: " << float1;
 std::cout << "\nlongdouble1: " << longdouble1;
 std::cout << "\ndouble2: " << double2;
 std::cout << "\nfloat2: " << float2;
 std::cout << "\ndouble3: " << double3;
 std::cout << "\nfloat3: " << float3;
 std::cout << "\n";

}</lang>

Output:

double1: 2.5
float1: 2.5
longdouble1: 2.5
double2: 0.0025
float2: 2500
double3: 16
float3: 190.934

Clojure

Clojure supports both standard and scientific notation.

user=> 1.
1.0
user=> 1.0
1.0
user=> 3.1415
3.1415
user=> 1.234E-10
1.234E-10
user=> 1e100
1.0E100
user=> (Float/valueOf "1.0f")
1.0

Clojure also supports returning ratios (fractions) if you divide integers. These are not subject to roundoff error. If you do specify a floating point in the division, it will return a floating point value.

user=> (/ 1 3)
1/3
user=> (/ 1.0 3)
0.3333333333333333

Common Lisp

The grammar for floating point literals in EBNF (ISO/IEC 14977):

float = [ sign ], { decimal-digit }, decimal-point, decimal-digit, { decimal-digit }, [exponent]  
      | [ sign ], decimal-digit, { decimal-digit }, [ decimal-point, { decimal-digit } ], exponent ;   
exponent = exponent-marker, [ sign ], decimal-digit, { decimal-digit } ;
sign = "+" | "-" ;
decimal-point = "." ;
decimal-digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
exponent-marker = "e" | "E" | "s" | "S" | "d" | "D" | "f" | "F" | "l" | "L" ;

Common Lisp implementations can provide up to 4 different float subtypes: short-float, single-float, double-float and long-float. The exponent marker specifies the type of the literal. "e"/"E" denotes the default floating point subtype (it is initially single-float but you can set it with the global variable *READ-DEFAULT-FLOAT-FORMAT* to any of the other subtypes). The standard only recommends a minimum precision and exponent size for each subtype and an implementation doesn't have to provide all of them:

Format       | Minimum Precision | Minimum Exponent Size  
--------------------------------------------------
Short (s/S)  |    13 bits        |      5 bits
Single (f/F) |    24 bits        |      8 bits
Double (d/D) |    50 bits        |      8 bits
Long (l/L)   |    50 bits        |      8 bits

Some examples:

> 1.0
1.0
> -.1
-0.1
> -1e-4
-1.0E-4
> 1d2
100.0d0
> .1f3
100.0
> .001l-300
1.0L-303

Note that 123. is not a floating point number but an integer:

> (floatp 123.)
NIL
> (integerp 123.)
T

D

D built-in floating point types include float (32-bit), double (64-bit) and real (machine hardware maximum precision floating point type, 80-bit on x86 machine) and respective complex number types. Here's information for Floating Literals.

Dyalect

Dyalect built-in types include only one floating point number of type Float (64-bit). Both regular and scientific notations are supported:

EBNF grammar for the floating point number is as follows:

float  = "." digit { digit } [ ("e"|"E") [ "+" | "-" ] digit { digit } ]
    | digit { digit } 
    ( 
        "." digit { digit } [ ( "e" | "E" ) ["+" | "-" ] digit { digit } ]
        | ( "e" | "E") ["+" | "-" ] digit { digit }
    ).

Eiffel

Floating point literals are of the form D.DeSD, where D represents a sequence of decimal digits, and S represents an optional sign. A leading "+" or "-" indicates a unary plus or minus feature and is not considered part of the literal.

Examples:<lang Eiffel> 1. 1.23 1e-5 .5 1.23E4 </lang>

Elena

Elixir

<lang elixir>iex(180)> 0.123 0.123 iex(181)> -123.4 -123.4 iex(182)> 1.23e4 1.23e4 iex(183)> 1.2e-3 0.0012 iex(184)> 1.23E4 1.23e4 iex(185)> 10_000.0 1.0e4 iex(186)> .5

- (SyntaxError) iex:186: syntax error before: '.'

iex(186)> 2. + 3

- (CompileError) iex:186: invalid call 2.+(3)

iex(187)> 1e4

- (SyntaxError) iex:187: syntax error before: e4</lang>

Erlang

Floating point literal examples: 1.0 , -1.0 , 1.2e3 , 1.2e-3 and 1.2E3 , 1.2E-3 .

Euphoria

<lang euphoria> printf(1,"Exponential:\t%e, %e, %e, %e\n",{-10.1246,10.2356,16.123456789,64.12}) printf(1,"Floating Point\t%03.3f, %04.3f, %+3.3f, %3.3f\n",{-10.1246,10.2356,16.123456789,64.12}) printf(1,"Floating Point or Exponential: %g, %g, %g, %g\n",{10,16.123456789,64,123456789.123}) </lang>

Output:

Exponential:    -1.012460e+001, 1.023560e+001, 1.612346e+001, 6.412000e+001
Floating Point  -10.125, 10.236, +16.123, 64.120
Floating Point or Exponential:  10, 16.1235, 64, 1.23457e+008

Factor

<lang factor>3.14 ! basic float +3.14 ! Optional signs -3.14 10e5 ! exponents signified by e or E 10E+5 ! with optional signs +10e-5 1. ! equivalent to 1.0 .5 ! equivalent to 0.5 1/2. ! floating point approximation of a ratio (0.5) 1/3. ! 0.3333333333333333 1/0. ! positive infinity -1/0. ! negative infinity 0/0. ! not-a-number

              ! hexadecimal, octal, and binary float literals are supported.
              ! they require a base 2 exponent expressed as a decimal
              ! preceded by p or P.

0x1.0p3 ! 8.0 -0x1.0P-3 ! -0.125 0b1.010001p3 ! 10.125 0o1.21p3 ! 10.125

              ! comma separators are allowed

1,234.123,456 ! 1234.123456

! normalized hex form ±0x1.MMMMMMMMMMMMMp±EEEE allows any floating-point ! number to be specified precisely according to IEEE 754 representation +0x1.1234567891234p+0002 ! 4.28444444440952</lang>

Fennel

<lang fennel>;;Numeric literals with a decimal component are treated as floating point. 3.14159 ;3.14159

2.3456e7 ;23456000.0

0x1234.abcd ;4660.6710968018 0x1234.56p3 ;37282.6875

123_456.789 ;123456.789 0x1234_5678.9a ;305419896.60156</lang>

Forth

Unlike most other languages, floating point literals in Forth are distinguished by their exponent ('E' or 'e') rather than their decimal point ('.' or ','). Numeric literals with just a decimal point are regarded as two-cell double precision integers. From the ANS Forth standards document:

Convertible string := <significand><exponent>

<significand> := [<sign>]<digits>[.<digits0>]
<exponent>    := E[<sign>]<digits0>
<sign>        := { + | - }
<digits>      := <digit><digits0>
<digits0>     := <digit>*
<digit>       := { 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 }

These are examples of valid representations of floating-point numbers in program source:

	1E   1.E   1.E0   +1.23E-1   -1.23E+1

Fortran

Floating-point literals involve a decimal point, otherwise they're integers. The rule is <sign><digits><.><digits><exponent> with each optional - except that there must be some digits! Spaces are irrelevant in source files, so 3 .141 159 would be acceptable, however when data are read, internal spaces are not allowed so "- 3.14" would be rejected - at least for free-format (or "list") style input. With formatted input, spaces are considered to be zeroes and a data field lacking a decimal point can have one assumed so that " 31" read by F4.1 would yield 3.1. There is no requirement that there be digits before the decimal point, nor digits after the decimal point (if there are digits before), so .5 and 5. are both acceptable.

The status of the sign is delicate, being a matter of context. In a DATA statement or in an assignment such as x = -5.5, the sign is a part of the number, but not in an arithmetic expression such as y = x*-5.5 which has two operators in a row and is rejected. x*(-5.5) is accepted and the sign is a part of the number.

The exponent part signifies a power of ten and if present, has the form <E or D><sign><integer>, the sign optional, where E signifies a single-precision number and D a double-precision number, irrespective of the number of digits offered in the number. Thus, a constant 3.14159265 will be double-precision only if there follows a D, presumably with a zero exponent. As a result, 1.0D0 is not the same as 1.0E0, even though they are equal, and a calculation such as 4*atan(1.0) will be in single precision unless it is 4*atan(1.0D0) or similar. Some compilers offer an option to regard all constants as being in double precision irrespective of E or D, but in the absence of that, 1.15 or 1.15E0 will not equal 1.15D0 because most decimal fractions are recurring sequences in binary, and if such constants were assigned to suitable variables and printed with one decimal digit, then on common computers, the double-precision value will come out as 10.2 because with 53-bit precision its value is (exactly) 10·1500000000000003552713678800500929355621337890625, which rounds up, while in single precision it is (exactly) 10·1499996185302734375, which rounds down.

There are also options for specifying constants as hexadecimal sequences, and if assigned to a floating-point variable, then Z"FFFFFFFFFFFFFFFF" will generate a (double precision) NaN value while Z"FFF0000000000000" will generate negative infinity, on cpus supporting such features. Similarly with octal and binary sequences. In these cases, the bit patterns are as they will be in the floating-point format, not as a number expressed in hexadecimal, etc. Thus, pi = Z"40490FDB" or 1000000010010010000111111011011, which is not 11.00100100001111110... at all.

Complex number constants are typically specified as (x,y) where x and y are floating-point literals; there is no provision for complex integers.

FreeBASIC

FreeBASIC has two floating point types : Single (4 bytes) and Double (8 bytes)

Numeric literals of these types can be specified by using the following suffixes:

Single !, f or F : Double #

However, this is not usually necessary as the compiler will automatically infer the type from the context and the two types are implicitly convertible to each other or explicitly convertible using the CSng or CDbl functions. However, conversions from Double to Single may lose precision.

All numeric literals which include a decimal point or exponent (i.e. scientific notation) are considered to be of floating point rather than integral type and are generally of the form:

number[.[fraction]][((D|E) [+|-] exponent)|(D|E)|][suffix]

or

.fraction[((D|E) [+|-] exponent)|(D|E)|][suffix]

Where scientific notation is used, D denotes Double precision and E denotes default precision , though these can be over-ridden by the suffix, if there is one. They can also be used on their own, without a following exponent.

The default precision is Double unless the 'QB' dialect of the language is used (for compatibility with QuickBasic code) where numbers of no more than 7 digits are considered to be Single precision.

Some examples, taken from the language documentation follow:

<lang freebasic>' FB 1.05.0 Win64 (default dialect)

Dim a As Double = 123.456 Dim b As Double = -123.0 Dim c As Double = -123.0d Dim d As Double = -123e Dim e As Double = 743.1e+13 Dim f As Double = 743.1D-13 Dim g As Double = 743.1E13 Dim h As Single = 743D! Rem ! overrides D Dim i As Single = 3.1! Dim j As Single = -123.456e-7f Dim k As Double = 0# Dim l As Double = 3.141592653589e3#</lang>

GAP

gecho

Go

See relevant section of language reference. Basically they are base 10, need either a decimal point or an exponent, and specify no precision or representation. The exponent can be signed, but the mantissa is not. One of the integer part or the fractional part may be elided; one of the decimal point or the exponent may be elided. A leading minus sign would be an operator and not part of the floating point literal. Examples,

0.
0.0
.0
1e3
1e-300
6.02E+23

Groovy

Solution: <lang groovy>println 1.00f // float (IEEE-32) println 1.00d // double (IEEE-64) println 1.00 // BigDecimal (scaled BigInteger) println 1.00g // BigDecimal println 1.00e0 // BigDecimal

assert 1.00f instanceof Float assert 1.00d instanceof Double assert 1.00 instanceof BigDecimal assert 1.00g instanceof BigDecimal assert 1.00e0 instanceof BigDecimal</lang>

Output:

1.0
1.0
1.00
1.00
1.00

Haskell

Haskell supports decimal representation of float literals, with or without an exponent. For more information, see the relevant portion of the Haskell 98 Report.

<lang haskell>main = print [0.1,23.3,35e-1,56E+2,14.67e1] </lang>

Output:

[0.1,23.3,3.5,5600.0,146.7]

Icon and Unicon

Real literals can be represented in two forms by (a) decimal literals, or (b) exponent literals. There is no sign as + and - are unary operators.

The program below shows a full range of valid real literals. <lang Icon>procedure main() every write( ![ 1., .1, 0.1, 2e10, 2E10, 3e-1, .4e2, 1.41e2, 8.e+3, 3.141e43 ]) end</lang>

The function write will cause the real values to be coerced as string constants. Icon/Unicon will format these as it sees fit resorting to exponent forms only where needed.

Library: Icon Programming Library

The IPL library routine printf provides a broader range of formatting choices.

J

This paragraph highlights current implementation specific details of internal types: J has a syntax for specifying numbers, but numeric constants are stored in their most compact implementation; for example, 2.1 is a floating point number, while 2.0 is an integer and 1.0 is a boolean. If the exact type of a value is important, an expression may be used; for example, 1.1-0.1 produces a floating point result.

J's numeric constant mini-language allows the specification of numbers which are not floating point, but as indicated above, numeric type in J is a semantic triviality and not a syntactic feature. (And this pervades the language. For example, 1+1 is 2, despite the result having a different type from both of the arguments. Or, for example, if maxint is the largest value represented using an integer type, maxint+1 will produce a floating point result instead of an error or a wraparound.)

Here is an informal bnf for J's numeric constant language. Note, however, that the implementation may disallow some unusual cases -- cases which are not treated as exceptional here (for example, the language specification allows 1.2e3.4 but the current implementation does not support fractional powers of 10 in numeric constants):

<lang bnf>numeric-constant ::= number-constant | number-constant whitespace numeric-constant whitespace ::= whitespacecharacter | whitespacecharacter whitespace whitespacecharacter ::= ' ' | TAB TAB is ascii 9 number-constant ::= arbitrary-constant | arbitrary-constant base-token base-constant base-token ::= 'b' | 'b-' base-constant ::= base-digits | base-digits '.' base-digits base-digits ::= base-digit | base-digit base-digits base-digit ::= digit | alpha1 | alpha2 alpha1 ::= 'a'|'b'|'c'|'d'|'e'|'f'|'g'|'h'|'i'|'j'|'k'|'l'|'m' alpha2 ::= 'n'|'o'|'p'|'q'|'r'|'s'|'t'|'u'|'v'|'w'|'x'|'y'|'z' arbitrary-constant ::= complex-constant | pi-constant | euler-constant | extended-constant pi-constant ::= complex-constant 'p' complex-constant euler-constant ::= complex-constant 'x' complex-constant extended-constant ::= signed-digits 'x' | signed-digits 'r' signed-digits complex-constant ::= exponential-constant | exponential-constant complex-token exponential-constant complex-token ::= 'ad' | 'ar' | 'j' exponential-constant ::= signed-constant | signed-constant 'e' signed-constant signed-constant ::= decimal-constant | '_' decimal-constant decimal-constant ::= digits | digits '.' digits signed-digits ::= digits | '_' digits digits ::= digit | digit digits digit ::= '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9'</lang>

e indicates exponential or scientific notation (number on left multiplied by 10 raised to power indicated by number on right)

ad, ar and j are used to describe complex numbers (angle in degrees, in radians, and rectangular form)

p and infix x are analogous to e except the base is pi or the base of natural logarithms

r and x are also used for arbitrary precision numbers, r indication a ration and a trailing x indicating an extended precision integer.

b is used for arbitrary bases, and letters a-z indicate digit values 10 through 35 when they follow a b

Floating point examples:

<lang j> 0 1 _2 3.4 3e4 3p4 3x4 0 1 _2 3.4 30000 292.227 163.794

  16bcafe.babe _16b_cafe.babe _10b11

51966.7 46818.7 _9</lang>

Note that all the values in an array are the same type, thus the 0, 1 and 2 in the above example are floating point because they do not appear by themselves. Note also that by default J displays no more than six significant digits of floating point values.

Java

<lang java>1. //double equal to 1.0 1.0 //double 2432311.7567374 //double 1.234E-10 //double 1.234e-10 //double 758832d //double 728832f //float 1.0f //float 758832D //double 728832F //float 1.0F //float 1 / 2. //double 1 / 2 //int equal to 0</lang> Values that are outside the bounds of a type will give compiler errors when trying to force them to that type.

jq

jq floating point literals are identical to JSON floating point literals. However, when jq parses a floating point or integer literal, conversion to IEEE 754 numbers takes place, which may result in a loss of accuracy and/or an apparent change of type, as illustrated by the following sequence of input => output pairs: <lang sh>1.0 => 1 1.2 => 1.2 1e10 => 10000000000 1e100 => 1e+100 1e1234 => 1.7976931348623157e+308 .1 => 0.1 .1e1 => 1</lang>

Julia

Works with: Julia version 0.6

<lang julia>0.1 .1 1. 1e-1 # scientific notation 1e+10 1e-10 0x01p-1 # hex float</lang>

Kotlin

<lang scala>val d: Double = 1.0 val d2: Double = 1.234e-10 val f: Float = 728832f val f2: Float = 728832F</lang>

Lasso

Lingo

<lang lingo>put 0.23 -- 0.2300

-- activate higher printing precision the floatPrecision = 8

put -.23 -- -0.23000000

put 9.00719925474099e15 -- 9.00719925474099e15

-- result is NOT a float put 2/3 -- 0

-- casting integer to float put float(2)/3 -- 0.66666667

-- casting string to float put float("0.23") -- 0.23000000</lang>

Lua

M2000 Interpreter

We can use Decimal using @ and Currency using # (no exponent part, both types)

<lang M2000 Interpreter> Def ExpType$(x)=Type$(x) Print ExpType$(-12)="Double", -12 Print ExpType$(12.)="Double", 12. Print ExpType$(12.e-5)="Double", 12.e-5 Print ExpType$(.1)="Double", .1 Print ExpType$(-12~)="Single", -12~ Print ExpType$(12.~)="Single", 12.~ Print ExpType$(12.e-5~)="Single", 12.e-5~ Print ExpType$(.1~)="Single", .1~ </lang>

Maple

Maple distinguishes "software floats" (of arbitrary precision) and "hardware floats" (of machine precision). To get the latter, use the "HFloat" constructor. <lang Maple> > 123.456; # decimal notation

                               123.456

> 1.23456e2; # scientific notation

                               123.456

> Float( 23, -2 ); # float constructor notation, by mantissa and exponent

                                 0.23

> Float( .123456, 3 ); # again

                               123.456

> Float( 1.23456, 2 ); # again

                               123.456

> Float( 12.3456, 1 ); # again

                               123.456

> HFloat( 1.23456, 2 ); # hardware float constructor

                           123.456000000000

> HFloat( 123.456 ); # again

                           123.456000000000

> 2.3^30; # large floats are printed using scientific notation

                                         11
                          0.7109434879 10

> 2/3; # NOT a float!

2/3

> evalf( 2/3 ); # but you can get one

                             0.6666666667

> 0.0; # zero

0.

> -0.0; # negative zero

-0.

> Float(infinity); # positive infinity

                           Float(infinity)

> Float(-infinity); # minus infinity

                           Float(-infinity)

> Float(undefined); # "NaN", not-a-number

                           Float(undefined)

</lang> Whether a given float is a software or hardware float can be determined by using "type". <lang Maple> > type( 2.3, 'hfloat' );

                                false

> type( HFloat( 2.3 ), 'hfloat' );

                                 true

</lang> (There is also a type "sfloat" for software floats, and the type "float", which covers both.)

Mathematica/Wolfram Language

<lang Mathematica>These numbers are given in the default output format. Large numbers are given in scientific notation. {6.7^-4,6.7^6,6.7^8} {0.00049625,90458.4,4.06068*10^6}

This gives all numbers in scientific notation. ScientificForm[%] {4.9625*10^(-4),9.04584*10^(4),4.06068*10^(6)}

This gives the numbers in engineering notation, with exponents arranged to be multiples of three. EngineeringForm[%] {496.25*10^(-6),90.4584*10^(3),4.06068*10^(6)}

In accounting form, negative numbers are given in parentheses, and scientific notation is never used. AccountingForm[{5.6,-6.7,10.^7}] {5.6,(6.7),10000000.}</lang>

Maxima

<lang maxima>/* Maxima has machine floating point (usually double precision IEEE 754), and arbitrary length "big floats" */

/* Here are ordinary floats */ 3.14159 2.718e0 1.2345d10 1.2345e10 1.2345f10

/* And big floats (always with a "b" for the exponent) */ 3.14159b0 2.718b0 1.2345b10

/* Before computing with big float, one must set precision to some value (default is 16 decimal digits) */ fpprec: 40$

bfloat(%pi); 3.141592653589793238462643383279502884197b0</lang>

Nemerle

3.14f                                   // float literal
3.14d, 3.14                             // double literal
3.14m                                   // decimal literal

Formally (from the Reference Manual):

<floating_point_literal> ::=
	[ <digits_> ] '.' <digits_> [ <exponent> ] [ <suffix> ]
|       <digits_> <exponent> [ <suffix> ]
|       <digits_> <suffix>
<exponent> ::=
	<exponential_marker> [ <sign> ] <digits>
<digits> ::=
	{ <digit> }
<digits_> ::=
	<digits> [ { '_' <digits> } ]
<exponential_marker> ::=
	'e'
|       'E'
<sign> ::=
	'+'
|       '-'
<digit> ::=
	<decimal_digit>
<suffix> ::=
	<floating_point_suffix>
<floating_point_suffix> ::=
	'f'
|       'd'
|       'm'

NetRexx

NetRexx supports decimal and exponential notation for floating point constants. A number in exponential notation is a simple number followed immediately by the sequence "E" (or "e"), followed immediately by a sign ("+" or "-"), followed immediately by one or more digits.

NetRexx supports floating point number notation in the primitive float and double types, it's built in Rexx object and any other Java object that supports floating point numbers.

<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols nobinary

numeric digits 40 -- make lots of space for big numbers numeric form scientific -- set output form for exponential notation

say 'Sample using objects of type "Rexx" (default):' fv = 1.5; say '1.5'.right(20) '==' normalize(fv).right(20) -- 1.5 fv = -1.5; say '-1.5'.right(20) '==' normalize(fv).right(20) -- -1.5 fv = 15e-1; say '15e-1'.right(20) '==' normalize(fv).right(20) -- 1.5 fv = 3e-12; say '3e-12'.right(20) '==' normalize(fv).right(20) -- 3E-12 fv = 3e+12; say '3e+12'.right(20) '==' normalize(fv).right(20) -- 3000000000000 fv = 17.3E-12; say '17.3E-12'.right(20) '==' normalize(fv).right(20) -- 1.73E-11 fv = 17.3E+12; say '17.3E+12'.right(20) '==' normalize(fv).right(20) -- 17300000000000 fv = 17.3E+40; say '17.3E+40'.right(20) '==' normalize(fv).right(20) -- 1.73E+41 fv = 0.033e+9; say '0.033e+9'.right(20) '==' normalize(fv).right(20) -- 33000000 fv = 0.033e-9; say '0.033e-9'.right(20) '==' normalize(fv).right(20) -- 3.3E-11 say

say 'Sample using primitive type "float":' ff = float ff = float 15e-1; say '15e-1'.right(20) '==' normalize(ff).right(20) -- 1.5 ff = float 17.3E-12; say '17.3E-12'.right(20) '==' normalize(ff).right(20) -- 1.73E-11 ff = float 17.3E+12; say '17.3E+12'.right(20) '==' normalize(ff).right(20) -- 17300000000000 ff = float 0.033E+9; say '0.033E+9'.right(20) '==' normalize(ff).right(20) -- 33000000 ff = float 0.033E-9; say '0.033E-9'.right(20) '==' normalize(ff).right(20) -- 3.3E-11 say

say 'Sample using primitive type "double":' fd = double fd = 15e-1; say '15e-1'.right(20) '==' normalize(fd).right(20) -- 1.5 fd = 17.3E-12; say '17.3E-12'.right(20) '==' normalize(fd).right(20) -- 1.73E-11 fd = 17.3E+12; say '17.3E+12'.right(20) '==' normalize(fd).right(20) -- 17300000000000 fd = 17.3E+40; say '17.3E+40'.right(20) '==' normalize(fd).right(20) -- 1.73E+41 fd = 0.033E+9; say '0.033E+9'.right(20) '==' normalize(fd).right(20) -- 33000000 fd = 0.033E-9; say '0.033E-9'.right(20) '==' normalize(fd).right(20) -- 3.3E-11 say

return

/**

* Convert input to a Rexx object and add zero to the value which forces NetRexx to change its internal representation
*
* @param fv a Rexx object containing the floating point value
* @return a Rexx object which allows NetRexx string manipulation methods to act on it
*/

method normalize(fv) private constant

 return fv + 0

</lang> Output:

Sample using objects of type "Rexx" (default): 
                 1.5 ==                  1.5 
                -1.5 ==                 -1.5 
               15e-1 ==                  1.5 
               3e-12 ==                3E-12 
               3e+12 ==        3000000000000 
            17.3E-12 ==             1.73E-11 
            17.3E+12 ==       17300000000000 
            17.3E+40 ==             1.73E+41 
            0.033e+9 ==             33000000 
            0.033e-9 ==              3.3E-11 
 
Sample using primitive type "float": 
               15e-1 ==                  1.5 
            17.3E-12 ==             1.73E-11 
            17.3E+12 ==       17300000000000 
            0.033E+9 ==             33000000 
            0.033E-9 ==              3.3E-11 
 
Sample using primitive type "double": 
               15e-1 ==                  1.5 
            17.3E-12 ==             1.73E-11 
            17.3E+12 ==       17300000000000 
            17.3E+40 ==             1.73E+41 
            0.033E+9 ==             33000000 
            0.033E-9 ==              3.3E-11

Nim

<lang nim>var x: float x = 2.3 x = 2.0 x = 0.3 x = 123_456_789.000_000_1 x = 2e10 x = 2.5e10 x = 2.523_123E10 x = 5.2e-10

var y = 2'f32 # Automatically a float32 var z = 2'f64 # Automatically a float64 </lang>

Objeck

OCaml

In the OCaml manual, the chapter lexical conventions describes floating-point literals, which are:

float-literal  ::=   [-] (0…9) { 0…9∣ _ } [. { 0…9∣ _ }] [(e∣ E) [+∣ -] (0…9) { 0…9∣ _ }]

Here are some examples:

<lang ocaml>0.5 1.0 1. (* it is not possible to write only "1" because OCaml is strongly typed,

        and this would be interpreted as an integer *)

1e-10 3.14159_26535_89793</lang>

Oforth

A literal floating point number is written with a . and with or without an exponential notation :

PARI/GP

Similar to C, but allowing only decimal. Also, GP allows a trailing decimal point:

[+-]?((\d*\.\d+\b)|(\d+(\.\d*)?[Ee][+-]?\d+\b)|-?(\.\d+[Ee][+-]?\d+\b)|(\d+\.))

PARI t_REAL numbers have a maximum value of

32-bit	$2^{2^{29}}(1-\epsilon )$	161,614,249 decimal digits
64-bit	$2^{2^{61}}(1-\epsilon )$	694,127,911,065,419,642 decimal digits

where $\epsilon$ is the machine epsilon at the selected precision. The minimum value is the opposite of the maximum value (reverse the sign bit).

0.0
0.  \\ == 0.0
.0  \\ == 0.0
.   \\ == 0.0
2e2
6.02e23
-2e48
1e-9
1e0

Pascal

1.345
-0.5345
5.34e-34

Perl

<lang perl># Standard notations: .5; 0.5; 1.23345e10; 1.23445e-10;

The numbers can be grouped:

100_000_000; # equals to 100000000 </lang>

Phix

Library: Phix/basics

Phix does not require any distinction between integers and floats: 5 and 5.0 are exactly the same. A variable declared as atom can hold an integer or a floating point value.
Division and other operators do what a sensible language should, eg 1/3 is 0.333333, not 0. [for the latter use floor(1/3)]
Floats cannot be expressed in any base other than decimal. They may optinally include a sign for mantissa and/or exponent.
It is not necessary for a digit to precede a decimal point, but one must follow it. Upper or lower e/g may be used.
In the 32-bit version, integers outside -1,073,741,824 to +1,073,741,823 must be stored as atoms. In the 64-bit version the limits of integers are -4,611,686,018,427,387,904 to +4,611,686,018,427,387,903.
On a 32-bit architecture floats can range from approximately -1e308 to +1e308 with 15 decimal digits, and on a 64-bit architecture they can range from approximately -1e4932 to +1e4932 with 19 decimal digits.
The included bigatom library allows working with extremely large integers and floats with arbitrary precision. In the following, '?x' is the Phix shorthand for 'print(1,x)', plus \n

?1e+12  -- (same as 1e12)
?1e-12
?5      -- (same as 5.0)
--?1.   -- (illegal, use 1 or 1.0)
?.1     -- (same as 0.1)
?1/3    -- 0.333333
printf(1,"%g %G\n",1e-30)

Output:

1e+12
1e-12
5
0.1
0.3333333333
1e-30 1E-30

PHP

More information about floating point numbers in PHP. <lang PHP>.12 0.1234 1.2e3 7E-10 </lang> Formal representation:

LNUM          [0-9]+
DNUM          ([0-9]*[\.]{LNUM}) | ({LNUM}[\.][0-9]*)
EXPONENT_DNUM [+-]?(({LNUM} | {DNUM}) [eE][+-]? {LNUM})

PicoLisp

PicoLisp does not support floating point literals in the base language, only fixed point (scaled) decimal integers of unlimited size and precision. See Numbers in the reference.

PL/I

<lang PL/I> 1.2345e-4 decimal floating-point 7e5 decimal floating-point 1.234_567_89e0 decimal floating-point. 1.0s0 decimal floating-point (single precision) 1.0d0 decimal floating-point (double precision) 1.34q0 decimal floating-point (quadruple/extended precision)

111.0101e7b binary floating-point equals 111.0101 * 2**7

                                    or 7.3125 * 2**7

1e5b binary floating-point equals 1 * 2**5 </lang>

PureBasic

Floating point literals do not need a decimal point if an exponent is used. They may also include a sign for the number or exponent.

-1.0   1.0  1.0E2  1.0E+2  1.0E-2  -1E2

Python

Works with: Python version 2.3.3

This is an excerpt of an ANTLR grammar for python obtained from here.

<lang ebnf>FLOAT

   :   '.' DIGITS (Exponent)?
   |   DIGITS '.' Exponent
   |   DIGITS ('.' (DIGITS (Exponent)?)? | Exponent)
   ;

DIGITS : ( '0' .. '9' )+ ;

Exponent

   :    ('e' | 'E') ( '+' | '-' )? DIGITS
   ;</lang>

Examples <lang python> 2.3 # 2.2999999999999998 .3 # 0.29999999999999999 .3e4 # 3000.0 .3e+34 # 2.9999999999999998e+33 .3e-34 # 2.9999999999999999e-35 2.e34 # 1.9999999999999999e+34 </lang>

Racket

lang racket

.2 2. 2.+0i ; zero imaginary part 2e0

x10.8 ; hex float
o1e2 ; oct float

2.0f0 ; single float 1.0t0 ; extended 80-bit float (when available on platform) </lang>

Output:

0.2
2.0
2.0
2.0
16.5
64.0
2.0f0
1.0t0

Raku

(formerly Perl 6) Floating point numbers (the Num type) are written in the standard 'e' scientific notation: <lang perl6>2e2 # same as 200e0, 2e2, 200.0e0 and 2.0e2 6.02e23 -2e48 1e-9 1e0</lang>

A number like 3.1416 is specifically not floating point, but rational (the Rat type), equivalent to 3927/1250. On the other hand, Num(3.1416) would be considered a floating literal though by virtue of mandatory constant folding.

REXX

All values in REXX are character strings, so a value could hold such things as these (decimal) numbers: <lang rexx>something = 127 something = '127' /*exactly the same as the above. */ something = 1.27e2 something = 1.27E2 something = 1.27E+2 something = ' + 0001.27e+00000000000000002 '</lang> To forcibly express a value in exponential notation, REXX has a built-in function format that can be used.

Note that a value of 0 (zero) in any form is always converted to

by the format BIF. <lang rexx>something = -.00478 say something say format(something,,,,0)</lang> output

-0.00478
-4.78E-3

The last invocation of format (above, with the 5th parameter equal to zero) forces exponential notation, unless the exponent is 0 (zero), then exponential notation won't be used.

There are other options for the format BIF to force any number of digits before and/or after the decimal point, and/or specifying the number of digits in the exponent.

Ruby

A Float literal is an optional sign followed by one or more digits and a dot, one or more digits and an optional exponent (e or E followed by an optional sign and one or more digits). Unlike many languages .1 is not a valid float.

Underscores can be used for clarity: 1_000_000_000.01

Rust

The fractional part may be elided (so 1. is valid) but the integer part may not (so .0 is not valid). <lang rust>2.3 // Normal floating point literal 3. // Equivalent to 3.0 (3 would be interpreted as an integer) 2f64 // The type (in this case f64, a 64-bit floating point number) may be appended to the value 1_000.2_f32 // Underscores may appear anywhere in the number for clarity.</lang>

Scala

Library: Scala

As all values in Scala, values are boxed with wrapper classes. The compiler will unbox them to primitive types for run-time execution. <lang Scala>1. //Double equal to 1.0 1.0 //Double, a 64-bit IEEE-754 floating point number (equivalent to Java's double primitive type) 2432311.7567374 //Double 1.234E-10 //Double 1.234e-10 //Double 758832d //Double 728832f //32-bit IEEE-754 floating point number (equivalent to Java's float primitive type) 1.0f //Float 758832D //Double 728832F //Float 1.0F //Float 1 / 2. //Double 1 / 2 //Int equal to 0

// Constants Float.MinPositiveValue Float.NaN Float.PositiveInfinity Float.NegativeInfinity

Double.MinPositiveValue Double.NaN Double.PositiveInfinity Double.NegativeInfinity </lang> Values that are outside the bounds of a type will give compiler-time errors when trying to force them to that type.

Scheme

<lang scheme> .2 ; 0.2 2. ; 2.0 2e3 ; 2000 2.+3.i ; complex floating-point number

in Scheme, floating-point numbers are inexact numbers

(inexact? 2.)

#t

(inexact? 2)

#f</lang>

Seed7

The type float consists of single precision floating point numbers. Float literals are base 10 and contain a decimal point. There must be at least one digit before and after the decimal point. An exponent part, which is introduced with E or e, is optional. The exponent can be signed, but the mantissa is not. A literal does not have a sign, + or - are unary operations. Examples of float literals are: <lang seed7> 3.14159265358979 1.0E-12 0.1234 </lang> The functions str and the operators digits and parse create and accept float literals with sign.

Original source: [1]

Sidef

Output:

Smalltalk

base 2 mantissa: <lang smalltalk>2r1010.0 -> 10.0 2r0.01 -> 0.25 2r1010e5 -> 320.0. "hint: = 10*(2ˆ5)"</lang>

base 2 mantissa and base 2 exponent: <lang smalltalk>2r1010e2r0101 -> 320.0 "hint: = 10*(2ˆ5)"</lang>

Complex numbers: <lang smalltalk>3.1i 2.0+4.5i</lang>

Stata

Only decimal floating-point are supported, computations are done in double precision (but storage can be made in integer or single floating-point as well).

Examples: <lang stata>.3 1.5 -1.5e10 3.15e-100</lang>

Swift

<lang Swift>let double = 1.0 as Double // Double precision let float = 1.0 as Float // Single precision let scientific = 1.0E-12

// Swift does not feature type coercion for explicit type declaration let sum = double + float // Error

let div = 1.1 / 2 // Double let div1 = 1 / 2 // 0</lang>

Tcl

Floating point literals in Tcl always contain either “.” or “e” (of any case), if not both, or are references to either one of the IEEE infinities or NaN. Formally, they are values that (case-insensitively) match one these regular expressions:

Normal values: [-+]?[0-9]*\.[0-9]+(e[-+]?[0-9]+)?; [-+]?[0-9]+\.?e[-+]?[0-9]+
Infinite values: [-+]?inf(inity)?
NaN values: [-+]?nan($[0-9a-f]+$)?

Note also that NaN values usually result in checked exceptions; they are supported mainly so that they can be handled when parsing and generating external binary data. All other floating-point literals are fully legal values. (Also note that this excludes the definition of integer literals; for details see this TIP document, which explains the whole state machine.)

Ursa

Cygnus/X Ursa (the standard Ursa interpreter) is written in Java and supports Java style floating-point literals. <lang ursa>1. 1.0 2432311.7567374 1.234E-10 1.234e-10 758832d 728832f 1.0f 758832D 728832F 1.0F</lang>

Verbexx

<lang verbexx>// Floating-point Literals: // // If present,the exponent must be of the form: // // eNNN...N // ENNN...N // e-NNN...N // E-NNN...N // e+NNN...N // E+NNN...N // // If present, length suffix must be: // // f F (FLOAT64_T) // f32 F32 (FLOAT32_T) // f64 F64 (FLOAT64_T) // fd Fd fD FD (FLOATD_T) -- boost::multiprecision:: // cpp_dec_float<100, int64_t> // // The presence of "." "E" "e" "F" or "f" indicates a floating point literal. // // A literal can start with "-" "." or a decimal digit, but not "+" or "_". // There must be at least one digit, so forms like ".F" ".e+11_f32" or just "." // are not recognized as floating point literals. // // Floating-point literal examples:

@SAY 0. .0 0.0 1. .1 123.123 ;// FLOAT64_T @SAY -0. -.0 -0.0 -1. -.1 -123.123 ;// FLOAT64_T

@SAY -0.E1 .0e0 0.0E6 -1.e6 -.1E8 12.12e44 -0E0 1e20 ;// FLOAT64_T @SAY -0.e+1 .0E+0 0.0e+6 -1.E+6 -.1e+8 12.12E+44 -0e+0 1E+20 ;// FLOAT64_T @SAY -0.E-1 .0e-0 0.0E-6 -1.e-6 -.1E-8 12.12e-44 -0E-0 1e-20 ;// FLOAT64_T @SAY -0E9999999999999999 .0e+9999999999 0.E-999999999999999999 ;// FLOAT64_T @SAY -8e0000000000000299 .6E+0000000299 5.e-000000000000000299 ;// FLOAT64_T

@SAY 0f -0f 0F -0f .0F -1234f 12.F 12.34f ;// FLOAT64_T @SAY 0F32 -0f32 0f32 -0f32 .0f32 -1234F32 12.f32 12.34F32 ;// FLOAT32_T @SAY 0f64 -0f64 0F64 -0f64 .0F64 -1234f64 12.F64 12.34f64 ;// FLOAT64_T @SAY 0fD -0fd 0FD -0fd .0Fd -1234fD 12.FD 12.34fD ;// FLOATD_T

@SAY -0.E1f .0e0F 0.0E6f64 -1.e6F64 -.1E8f 12.12e44f64 -0E0F 1e20f64 ;// FLOAT64_T @SAY -0.e+1f32 .0E+0F32 0.0e+6f32 -1.E+6F32 -.1e+8f32 12.12E+34F32 -0e+0f32 1E+20F32;// FLOAT32_T @SAY -0.E-1fd .0e-0fD 0.0E-6Fd -1.e-6FD -.1E-8fd 12.12e-44fD -0E-0Fd 1e-20FD ;// FLOATD_T @SAY -0E9999999999999999f32 .0e+9999999999F32 0.E-999999999999999999f32 ;// FLOAT32_T @SAY -8e0000000000000299f .6E+0000000299f64 5.e-00000000000000000000299F64 ;// FLOAT64_T @SAY -8e9999999999999999fD .6E+99999999999fD 5.e-12345678987654321FD ;// FLOATD_T

// note: _ (underscores) can appear in the main numeric part of the literal // after the first digit and before any length suffix:

@SAY -10_000__f 1__0._55__ -1__.__ .0___44 1_._2__E-23F32 debug:;

// Underscores can also appear in the exponent, after the first digit:

@SAY -1_E-0__2_f32 1.e+0___5_5____ -1.0_E123_456_789_987_654_321__fD debug:;</lang>

Vim Script

There are two ways to write floating point literals:

[-+]?[0-9]+\.[0-9]+
[-+]?[0-9]+\.[0-9]+[eE][-+]?[0-9]+

Examples: 12.34 +0.34 -1.0 12.34e5 0.99e-2 -1.0E+4

Note that there must always be at least one digit before and after the period (and for the exponent).

Visual Basic

Works with: Visual Basic version 5

Works with: Visual Basic version 6

Works with: VBA version Access 97

Works with: VBA version 6.5

Works with: VBA version 7.1

<lang vb>Sub Main() Dim d As Double ' 8 Bytes, type specifier = # Dim s As Single ' 4 Bytes, type specifier = !

 d = -12.3456
 d = 1000#
 d = 0.00001
 d = 67#
 d = 8.9
 d = 0.33
 d = 0#
 d = 2# * 10 ^ 3
 d = 2E+50
 d = 2E-50
 s = -12.3456!
 s = 1000!
 s = 0.00001!
 s = 67!
 s = 8.9!
 s = 0.33!
 s = 0!
 s = 2! * 10 ^ 3

End Sub</lang> There is no built-in support for not-a-number, but here's a way to handle that anyway: <lang vb>Option Explicit Public Declare Function RtlCompareMemory Lib "ntdll.dll" _

 (ByRef Source1 As Any, ByRef Source2 As Any, ByVal Length As Long) As Long

Public Function IsNAN(ByRef d As Double) As Boolean Dim d1 As Double

   d1 = NaN()
   IsNAN = (RtlCompareMemory(d, d1, 8) = 8)

End Function

Public Function NaN() As Double

   On Error Resume Next ' ignore the error
   NaN = 0 / 0

End Function

Sub Main() Dim d1 As Double Dim d2 As Double

   d1 = NaN()
   d2 = d1
   Debug.Assert IsNAN(d2)
   Debug.Print CStr(d2)

End Sub</lang>

Output:

-1,#IND

Wren

Wren has just one kind of floating point literal which must have digits both before and after the decimal point. Forms such as 123. and .123 are not allowed.

Negative zero can be represented directly but infinities or NaN cannot.

It is also possible to represent floating point numbers using scientific notation.

All numbers are instances of the built-in Num class which is always 8 bytes in size. Integers are really just floating point numbers which have no decimal part. <lang ecmascript>var f = 123.45 var g = 0.12345 // .12345 not allowed var h = 1.234e2 var i = -0.0 System.print([f, g, h, i])</lang>

Output:

[123.45, 0.12345, 123.4, -0]

XPL0

zkl

zkl requires something on both sides of the dot for a thing to be a float <lang zkl>1.0, 0.1, 3.1415, 1.e-100, 1.2e100, -1e10, -1e+10, 123.456E-300</lang>