Java Reference
In-Depth Information
program to jump to the line immediately after the
while
statement regardless of the value
of the
while
condition. For example, our multiplication program can be rewritten as follows.
import
java . util .
∗
;
public class
Arithmetic
{
public static void
main(String [] args)
{
int
x=(
int
) (Math . random ( )
∗
10) ;
int
y=(
int
) (Math . random ( )
∗
10) ;
Scanner keyboard =
new
Scanner(System. in) ;
int
z;
do
System. out . print (x +
"*"
+y+
"="
);
z = keyboard . nextInt () ;
if
(z==x
{
∗
y)
break
;
}
{
System. out . println (
"This is incorrect!"
);
else
}
}
while
(
true
);
System. out . println (
"This is correct!"
);
}
}
The program checks if the variable
z
is equal to
x*y
. If it is, the program breaks out of
the
do-while
statement. Otherwise, it prints that the guess was wrong and starts executing
the loop again. Note that the
break
statement can be used to escape from both
while
and
do-while
loops and from a
switch
block. In general, the
break
statement can be used to
escape from any loop or a
switch
block. However, the
break
statement cannot be used to
escape from any other block, including an
if
block.
3.3 The
for
Loop
Next, let us play a guessing the game. The computer will think of a random number
between 0 and 999. We will have 10 tries to guess the number. Every time we guess, we
will be told if the number is lower or higher. In this program, we need to perform a task at
most 10 times. One way to do so is to use a
while
loop that keeps track of the number of
guesses. A
break
statement can be executed when the number is guessed before the tenth
try. Here is a code snippet of the program.
...
int
numTries = 0;
while
(numTries
<
=9)
{
...
numTries = numTries+1;
}
...
The
while
statement will be executed for
numTries
= 0 to 9, that is, a total of 10 times.
In general, the easiest way to execute something 10 times is to create a counter that keeps
track of how many times it is executed. One needs a loop that keeps executing the block
until the counter reaches a predetermined value. This is similar to going to the gym and
running ten laps. You need to keep track of how many laps you have run and stop when this
