Conditionals and Loops - Java Software Solutions: Foundations of Program Design - page 230

5.4 The while Statement

As we discussed in the introduction of this chapter, a repetition statement (or
loop) allows us to execute another statement multiple times. A while statement is
a loop that evaluates a boolean condition just as an if statement does and exe-
cutes a statement (called the body of the loop) if the condition is true. However,
unlike the if statement, after the body is executed, the condition is evaluated
again. If it is still true, the body is executed again. This repetition continues until
the condition becomes false; then processing continues with the statement after
the body of the while loop. Figure 5.7 shows this processing.

While Statement

switch ( Expression ) { }

Switch Case

The while loop repeatedly executes the specified Statement as long
as the boolean Expression is true. The Expression is evaluated first;
therefore the Statement might not be executed at all. The Expression is
evaluated again after each execution of Statement until the Expression
becomes false.
Example:
while (total > max)
{
total = total / 2;
System.out.println ("Current total: " + total);
}

condition
evaluated

true false

statement

FIGURE 5.7 The logic of a while loop