Every conditional block begins with an
if statement and ends with
and
endif statement. Within the
if statement,
the control expression inside the parentheses is evaluated first. If the value of
the control expression is zero or
false and there is an
else statement, then the statement following the
else statement is executed. If there is no
else, the statement following
endif is
executed. If the value of the control expression evaluates to any other value, the
expression is
true and the statement following the
if is executed. A multiway decision can be expressed as a
series of
elseif statements within the control block. Such a
control decision block looks like
this:
{if (expr)}
templex statements1
{elseif(expr)}
templex statements2
{elseif(expr)
templex statements3
{else}
templex statements4
{endif}