while
loop is a pre-checking loop. This means a condition is
evaluated before an iteration is performed. The general form of
a while
statement is as follows:
'while' '('<bexpr>')' <stmt>
<bexpr>
is also called a precondition. <stmt>
executes if and only if <bexpr<>
evaluates to true. However,
after <stmt>
executes, <bexpr>
is evaluated again to
see if another iteration is necessary.