Booleans [AX 2012]

Updated: September 21, 2011

Applies To: Microsoft Dynamics AX 2012 R3, Microsoft Dynamics AX 2012 R2, Microsoft Dynamics AX 2012 Feature Pack, Microsoft Dynamics AX 2012

The boolean data type contains a value that evaluates to either true or false. You can use the X++ reserved literals true and false where ever a Boolean expression is expected.

Boolean expressions are also named logical expressions.

In X++ the internal representation of a boolean is an integer. You can assign any integer value to a variable declared of type boolean. The integer value 0 (zero) evaluates to false, and all others evaluate to true.

The X++ literal false is the integer value 0, and true is 1.

The following table lists several expressions and indicates whether they evaluate to true or false.

Expression

Boolean value

1

True

44

True

true

True

(false == 0)

True

(true == 1)

True

(true == 8)

False

false

False

0

False

Boolean declaration

=

boolean variable { , variable } ;

variable

=

identifier [ option ]

option

=

Arrayoptions | initialization

// Simple declaration of a boolean variable, b
boolean b; 
 
// Multiple declaration
boolean b1,b2;
 
// Boolean variable is initialized to true 
boolean b3 = true; 
 
// Declares a dynamic array of Booleans
boolean b4[]; 

Because the internal representation of a boolean is an integer, boolean values are automatically converted into integers and reals.

You usually use Booleans in conditional statements, or as parts or results of logical expressions. The following example shows both.

void main()
{
    //Declares a boolean called exprValue
    boolean exprValue; 
 
    //Assigns ExprValue the truth value of (7*6 == 42)
    exprValue = (7*6 == 42);
    ;
 
    if (exprValue)
    { 
        print "OK";
    } 
}

Here, the variable exprValue contains the value true, because 7*6 is equal to 42; so, the expression is true. The conditional statement is true; the word "OK" is displayed on the screen.

Keyword

boolean

Size of data type

Byte

Scope of data type

false (0) and true (1)

Default value

false

Implicit conversions

Automatically converted to int, date, and real

Explicit conversions

none


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