Boolean values: Difference between revisions

Line 28:

=={{header|8th}}==

In 8th, any non-zero number is true, as is the specific boolean value 'true'. Everything else evaluates as 'false' (including the boolean value, 'false')

=={{header|AArch64 Assembly}}==

Line 82:

Line 83:

.include "../includeARM64.inc"

</lang>

=={{header|ACL2}}==

Same as [[Common Lisp|Boolean Values#Common Lisp]].

Line 343:

Line 345:

110 END</lang>

==={{~~Header~~|BaCon}}===

==={{header|BaCon}}===

<lang qbasic>' Boolean TRUE and FALSE are non-zero and zero constants

a = TRUE

Line 376:

Line 378:

print true

</lang>

=={{header|Batch File}}==

Line 441:

Line 442:

* in C99, the boolean type <code>bool</code> (defined in header <tt><stdbool.h></tt>), where <code>true</code> gives true and <code>false</code> gives false

* in C99, any [[Complex numbers|complex number]] type, where 0 (0 real and 0 imaginary) gives false, anything else gives true

=={{header|C sharp|C#}}==

In C#, there are the reserved keywords <code>true</code> and <code>false</code>. Variables to hold these values are declared as either <code>bool</code> or <code>Boolean</code>. These types are identical, as <code>bool</code> is just shortand for <code>Boolean</code>. The collection type <code>BitArray</code> returns its values as <code>Boolean</code>, packing 8 values into each byte (In contrast, the <code>Boolean</code> type uses the entire byte for one value).

Unlike C/C++, there is no conversion in C# between other types and <code>Boolean</code>.

=={{header|C++}}==

Line 449:

Line 455:

* any pointer type, where the null pointer gives false and any other pointer gives true

* any user-defined type with an implicit conversion operator either to <code>bool</code> or to a built-in type which itself can be converted to <code>bool</code> (i.e. any of the above). The C++ standard library contains one such implicit conversion: the implicit conversion of a stream <code>s</code> to <code>bool</code> gives <code>!s.fail()</code>

=={{header|C sharp|C#}}==

In C#, there are the reserved keywords <code>true</code> and <code>false</code>. Variables to hold these values are declared as either <code>bool</code> or <code>Boolean</code>. These types are identical, as <code>bool</code> is just shortand for <code>Boolean</code>. The collection type <code>BitArray</code> returns its values as <code>Boolean</code>, packing 8 values into each byte (In contrast, the <code>Boolean</code> type uses the entire byte for one value).

Unlike C/C++, there is no conversion in C# between other types and <code>Boolean</code>.

=={{header|Clean}}==

Line 580:

Line 581:

]

</lang>

=={{header|Common Lisp}}==

Line 615:

=={{header|Delphi}}==

In addition to the types defined by [[#Object Pascal|Object Pascal]], Delphi defines the type <code>Bool</code>.

=={{header|Déjà Vu}}==

Déjà Vu has <code>true</code> and <code>false</code>, two numbers that are equal to 1 and 0 respectively. Every object has a truth value. The only falsy things are numbers equal to zero, empty lists and dictionaries, and zero-length strings and blobs.

=={{header|DWScript}}==

Line 631:

Line 627:

#f // <boolean> false</lang>

For the purpose of conditional statements, all objects other than <tt>#f</tt> evaluate to true.

=={{header|Déjà Vu}}==

Déjà Vu has <code>true</code> and <code>false</code>, two numbers that are equal to 1 and 0 respectively. Every object has a truth value. The only falsy things are numbers equal to zero, empty lists and dictionaries, and zero-length strings and blobs.

=={{header|E}}==

Line 663:

(not 0) → #f

</lang>

=={{header|EGL}}==

Line 706:

Line 704:

myInt: true

</pre>

=={{header|Elena}}==

Line 841:

Line 838:

TYPE(MIXED) STUFF</lang>

Except that now only hundred-element variables of type MIXED can be declared. Either way, the record size needed for a disc file holding such items will need careful thought.

=={{header|Free Pascal}}==

In addition to the types defined by [[#Object Pascal|Object Pascal]], free Pascal defines the <code>qWordBool</code>, that has a <code>sizeOf</code> eight.

=={{header|FreeBASIC}}==

Line 877:

-1

</pre>

=={{header|Free Pascal}}==

In addition to the types defined by [[#Object Pascal|Object Pascal]], free Pascal defines the <code>qWordBool</code>, that has a <code>sizeOf</code> eight.

=={{header|Futhark}}==

Line 1,097:

Line 1,094:

* String: the empty (zero-length) string is <code>false</code>; otherwise <code>true</code>

`

=={{header|Kotlin}}==

Booleans in Kotlin are given by the literals true and false, case sensitive, which are the only instances of the class Boolean.

Line 1,269:

Line 1,267:

=={{header|Mathematica}}==

True and False are the default boolean values.

To make any expression a boolean use the Boole[] function.

=={{header|MATLAB}}==

The keywords "true" and "false" are the default boolean values.

Line 1,331:

Line 1,329:

Metafont has the type <tt>boolean</tt>; a boolean variable can be <tt>true</tt> or <tt>false</tt>.

Using non boolean values (or expressions that do not evaluate to a boolean value) results in a recoverable error; by default, any non-boolean value is interpreted as false.

=={{header|Microsoft Small Basic}}==

Microsoft Small Basic has two constants: <code>"True"</code> and <code>"False"</code>.<br>

<lang smallbasic>If c Then

notc = "False"

Else

notc = "True"

EndIf</lang>

=={{header|min}}==

Line 1,506:

Line 1,512:

$istrue(0) tests false

$istrue(1) tests true</pre>

=={{header|Nemerle}}==

Line 1,546:

Line 1,551:

0 is false

</pre>

=={{header|Microsoft Small Basic}}==

Microsoft Small Basic has two constants: <code>"True"</code> and <code>"False"</code>.<br>

<lang smallbasic>If c Then

notc = "False"

Else

notc = "True"

EndIf</lang>

=={{header|Nim}}==

Line 1,574:

Line 1,571:

=={{header|Objeck}}==

Objeck has a <tt>Bool</tt> type that is set to either <tt>true</tt> or <tt>false</tt>. By default boolean types are initialized to <tt>false</tt>. The boolean type also allows methods to be invoked, which perform simple conversions or print given values.

=={{header|Objective-C}}==

Objective-C follows pretty much the same rules as C. In addition to C, Objective-C has a <code>BOOL</code> boolean type, with values <code>YES</code> for true and <code>NO</code> for false. Objective-C also adds several special types of pointers; for pointers to objects (values of type <code>id</code>), the <code>nil</code> pointer is false, everything else is true; for pointers to classes (values of type <code>Class</code>), the <code>Nil</code> pointer is false, everything else is true.

=={{header|Object Pascal}}==

Line 1,586:

Line 1,580:

''See also [[#Delphi|Delphi]] and [[#Free Pascal|Free Pascal]]''

=={{header|Objective-C}}==

Objective-C follows pretty much the same rules as C. In addition to C, Objective-C has a <code>BOOL</code> boolean type, with values <code>YES</code> for true and <code>NO</code> for false. Objective-C also adds several special types of pointers; for pointers to objects (values of type <code>id</code>), the <code>nil</code> pointer is false, everything else is true; for pointers to classes (values of type <code>Class</code>), the <code>Nil</code> pointer is false, everything else is true.

=={{header|OCaml}}==

Line 1,688:

Line 1,685:

As a special case, literal <tt>1</tt>s and <tt>0</tt>s will never cause a "Useless use of a constant in void context" warning. Another special case worth pointing out here is that the string <tt>'0 but true'</tt> won't provoke a warning if it's used as a number.

=={{header|Perl 6}}==

Perl 6 provides an enumeration <code>Bool</code> with two values, <code>True</code> and <code>False</code>. Values of enumerations can be used as ordinary values or as mixins:

<lang perl6>my Bool $crashed = False;

my $val = 0 but True;</lang>

For a discussion of Boolean context (i.e. how Perl decides whether something is true or false), see [http://perlcabal.org/syn/S02.html#Context Synopsis 2].

=={{header|Phix}}==

Line 1,759:

Line 1,746:

=={{header|Pony}}==

Boolean values are <code>true</code> and <code>false</code>. Conditions must have type Bool, i.e. they are always true or false.

=={{header|PostScript}}==

Predefined constants are:

<lang postscript>true

false</lang>

=={{header|PowerBASIC}}==

Line 1,769:

Line 1,762:

x = ISFALSE(1 = 1) ' returns 0

x = ISFALSE(1 = 0) ' returns -1</lang>

=={{header|PostScript}}==

Predefined constants are:

<lang postscript>true

false</lang>

=={{header|PowerShell}}==

Line 1,857:

Line 1,844:

... evaluates to <tt>'pear</tt>, because <tt>'bloggle</tt> is not false.

=={{header|Raku}}==

(formerly Perl 6)

Perl 6 provides an enumeration <code>Bool</code> with two values, <code>True</code> and <code>False</code>. Values of enumerations can be used as ordinary values or as mixins:

<lang perl6>my Bool $crashed = False;

my $val = 0 but True;</lang>

For a discussion of Boolean context (i.e. how Perl decides whether something is true or false), see [http://perlcabal.org/syn/S02.html#Context Synopsis 2].

=={{header|Raven}}==

Line 1,989:

Line 1,987:

=={{header|Self}}==

Self has two objects, ''true'' and ''false''.

=={{header|SenseTalk}}==

True, Yes, and On are true; False, No, Off and Empty (an empty string) are false.

Line 2,157:

Line 2,156:

True False True False

</pre>

=={{header|Visual Basic}}==

VB has the <code>Boolean</code> data type and the constants <code>True</code> and <code>False</code>, in addition to what's listed under [[#BASIC|BASIC]], above. When used outside of a boolean context, <code>True</code> and <code>False</code> return values depending on their context -- <code>-1</code> and <code>0</code> in a numeric context, <code>"True"</code> and <code>"False"</code> if used as strings.

<br>When converting an integer to a boolean, <code>0</code> is <code>False</code> and anything not equal to <code>0</code> is

<lang vb>Dim x As Boolean

x = IIf(Int(Rnd * 2), True, False)

MsgBox x</lang>

=={{header|Vim Script}}==

Line 2,176:

Line 2,166:

echo "false"

endif</lang>

=={{header|Visual Basic}}==

VB has the <code>Boolean</code> data type and the constants <code>True</code> and <code>False</code>, in addition to what's listed under [[#BASIC|BASIC]], above. When used outside of a boolean context, <code>True</code> and <code>False</code> return values depending on their context -- <code>-1</code> and <code>0</code> in a numeric context, <code>"True"</code> and <code>"False"</code> if used as strings.

<br>When converting an integer to a boolean, <code>0</code> is <code>False</code> and anything not equal to <code>0</code> is

<lang vb>Dim x As Boolean

x = IIf(Int(Rnd * 2), True, False)

MsgBox x</lang>

=={{header|WDTE}}==