Java Reference
In-Depth Information
Scope of
do
Variables
A variable declared within the block of a
do
statement only has scope within that block.
Be aware that the
boolean
expression of a
do
statement is outside the block, so the
following code does not compile:
17. do {
18. int one = rollDice();
19. int two = rollDice();
20. System.out.println(“You rolled a “ + (one + two));
21. }while(one + two != 11);
The variables
one
and
two
are out of scope on line 21. For this loop to work,
one
and
two
need to be declared outside of the
do
statement.
Now that we have discussed the various looping control structures in Java, I want to discuss
two important keywords that affect the fl ow of control of loops:
break
and
continue
. Let's
start with a discussion of the
break
statement.
The
break
Statement
The exam objectives state that you should be able to “develop code that implements
all forms of loops and iterators, including the use of break.” A
break statement
transfers
fl ow of control out of an enclosing statement. A
break
statement can appear within the
following control structures:
switch
for
while
do
Figure 3.7 shows the syntax for a
break
statement within a
while
statement. (The
syntax is similar for the other control structures.)
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