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dec_c_help.HLP
break
The break statement terminates the immediately enclosing while, do,
for, or switch statement. Control passes to the statement
following the terminated statement.
Syntax:
break ;
continue
The continue statement passes control to the test portion of the
immediately enclosing while, do, or for statement.
Syntax:
continue ;
In each of the following statements, a continue statement is
equivalent to "goto label;":
while (expression) { statement ... label: ; }
do { statement ... label: ; } while (expression);
for (expression; expression; expression)
{ statement ... label: ; }
The continue statement is not intended for switches. A continue
statement inside a switch statement inside a loop causes
reiteration of the loop.
do
The do statement executes a statement one or more times, as long as
a stated condition expression is true.
Syntax:
do statement while ( expression ) ;
The do statement is executed at least once. The expression is
evaluated after each execution of the statement. If the expression
is not 0, the statement is executed again. The statement following
the do statement (the body of the do statement) is not optional;
the null statement (a lone semicolon) is provided for specifying a
do statement with an empty body.
for
The for statement executes a statement zero or more times, with
three specified control expressions. Expression-1 is evaluated
only once, before the first iteration; expression-2 is evaluated
before every iteration; expression-3 is evaluated after every
iteration. The for loop terminates if, on evaluation, expression-2
is 0.
Syntax:
for ( [expression-1] ; [expression-2] ; [expression-3] )
statement
The for statement is equivalent to the following format:
expression-1;
while ( expression-2 ) { statement expression-3; }
You can omit any of the three expressions. If expression-2 is
omitted, the while condition is true.
goto
The goto statement transfers control unconditionally to a labeled
statement.
Syntax:
goto identifier ;
The identifier must be a label located in the current function.
You may use goto to branch into a block, but no initializations are
performed on variables declared in the block.
if
The if statement is a conditional statement. It can be written
with or without an else clause as follows:
if ( expression ) statement
if ( expression ) statement else statement
In both cases, the expression is evaluated, and if it is not 0, the
first statement is executed. If the else clause is included and
the expression is 0, the statement following else is executed
instead. In a series of if-else clauses, the else matches the most
recent else-less if.
Labeled
Any statement can be preceded by a label prefix of the following
form:
identifier:
This declares the identifier as a label. The scope of such a
declaration is the current function. Labels are used only as the
targets of goto statements.
Null
A null statement is a semicolon:
;
The null statement provides a null action -- for example, the body
of a for loop that takes no action:
for(i=0; i < ARRAYSIZE && x[i] == 5; i++)
;
return
The return statement causes a return from a function, with or
without a return value.
Syntax:
return ;
return expression ;
The return value is undefined if not specified in a return
statement. If an expression is specified in the return statement,
it is evaluated and the value is returned to the calling function;
the value is converted, if necessary, to the type with which the
called function was declared. If a function does not have a return
statement, the effect (on reaching the end of the function) is the
same as with a return statement that does not specify an
expression. Functions declared as void may not contain return
statements specifying an expression.
switch
The switch statement executes one or more of a series of cases,
based on the value of an integer expression.
Syntax:
switch ( expression ) body
The switch's body typically is a block, within which any statement
can be prefixed with one or more case labels as follows:
case constant-expression :
At most one statement in the body may have the label as follows:
default :
The switch expression is evaluated and compared to the cases. If
there is a case matching the expression's value, it is executed; if
not, the default case is executed. The switch is normally
terminated by a break, return, or goto statement in one of the
cases. If there is no matching case and no default, the body of
the switch statement is skipped.
while
The while statement executes a statement 0 or more times, as long
as a stated condition is true.
Syntax:
while ( expression ) statement
The expression is evaluated before each execution, and the
statement is executed if the expression is not 0. The statement
following the parentheses (the body of the while statement) is not
optional; the null statement (a lone semicolon) is provided for
specifying a while statement with an empty body.
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