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DEVELOPING
COLDFUSION 9 APPLICATIONS
The CFML Programming Language
Las
t
upda
te
d 8/5/2010
Operator types
ColdFusion has Five types of operators:
•
Arithmetic
•
Boolean
•
Decision (or comparison)
•
String
•
Ternary
Functions also can be viewed as operators because they act on operands.
Arithmetic operators
The following table describes the arithmetic operators:
Boolean operators
Boolean, or logical, operators perform logical connective and negation operations. The operands of Boolean operators
are Boolean (True/False) values. The following table describes the Boolean operators:
Operator
Description
+ - * /
Basic arithmetic: Addition, subtraction, multiplication, and division.
In division, the right operand cannot be zero.
++ --
Increment and decrement. Increase or decrease the variable by one.
These operators can be used for pre-incrementing or decrementing (as in
x = ++ i
), where the variable is
changed before it is used in the expression. They can also be used for post-incrementing or decrementing (as in
x = i++
), where the value is changed after it is used in the expression. If the value of the variable
i
is initially 7,
for example, the value of
x
in
x = ++i
is 8 after expression evaluation, but in
x=i++
, the value of
x
is 7. In both
cases, the value of
i
becomes 8.
These operators cannot be used with expressions that involve functions, as in
f().a++
. Also, you can use an
expression such as
-++x
, but
---x
and
+++x
cause errors, because their meanings are ambiguous. You can use
parentheses to group the operators, as in
-(--x)
or
+(++x)
, however.
+= -= *= /= %=
Compound assignment operators. The variable on the right is used as both an element in the expression and the
result variable. Thus, the expression
a += b
is equivalent to
a = a +b
.
An expression can have only one compound assignment operator.
+ -
Unary arithmetic: Set the sign of a number.
MOD
or %
Modulus: Return the remainder after a number is divided by a divisor. The result has the same sign as the divisor.
The value to the right of the operator should be an integer; using a non-numeric value causes an error, and if you
specify a real number, ColdFusion ignores the fractional part (for example, 11 MOD 4.7 is 3).
\
Integer division: Divide an integer by another integer. The result is also an integer; for example, 9\4 is 2. The right
operand cannot be zero.
^
Exponentiation: Return the result of a number raised to a power (exponent). Use the caret character (^) to
separate the number from the power; for example, 2^3 is 8. Real and negative numbers are allowed for both the
base and the exponent. However, any expression that equates to an imaginary number, such -1^.5 results in the
string "-1.#IND. ColdFusion does not support imaginary or complex numbers.
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