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.