MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX, Руководство по разработке

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134 Chapter 6: Extending ColdFusion Pages with CFML Scripting
•
The statements following the colon in a
case
statement block do not have to be in braces. If a
constant value equals the
switch
expression, ColdFusion executes all statements through the
break
statement.
•
The
break
statement at the end of the
case
statement tells ColdFusion to exit the
switch
statement. ColdFusion does not generate an error message if you omit a
break
statement.
However, if you omit it, ColdFusion executes all the statements in the following case
statement,
even if that case is false . In nearly all circumstances, this is not what you want to do.
•
You can have only one
default
statement in a
switch
statement block. ColdFusion executes
the statements in the
default
block if none of the
case
statement constants equals the
expression value.
•
The
default
statement does not have to follow all
switch
statements, but it is good
programming practice to do so. If any
switch
statements follow the
default
statement you
must end the
default
block code with a
break
statement.
•
The
default
statement is not required. However, you should use one if the
case
constants do
not include all possible values of the expression.
•
The
default
statement does not have to follow all the
case
statements; however, it is good
programming practice to put it there.
The following
switch
statement takes the value of a name variable:
1
If the name is John or Robert, it sets both the male variable and the found variable to True.
2
If the name is Mary, it sets the male variable to False and the found variable to True.
3
Otherwise, it sets the found variable to False.
switch(name) {
case "John": case "Robert":
male=True;
found=True;
break;
case "Mary":
male=False;
found=True;
break;
default:
found=False;
} //end switch
Using looping statements
CFScript provides a richer selection of looping constructs than those supplied by CFML tags. It
enables you to create efficient looping constructs similar to those in most programming and
scripting languages. CFScript provides the following looping constructs:
•
For
•
While
•
Do-while
•
For-in
CFScript also includes the
continue
and
break
statements that control loop processing.
The following sections describe these types of loops and their uses.