Java Reference
In-Depth Information
public class
Test
{
public static void
main(String [] args)
{
System. out . println (
"Please enter a decimal number: "
);
Scanner keyboard =
new
Scanner(System. in) ;
int
number = keyboard . nextInt () ;
String result =
""
;
while
(number
>
0)
{
int
remainder = number % 16;
if
(remainder
<
=9)
{
result = remainder+result ;
}
else
{
result = (
char
)(
'A'
+remainder
−
10)+resul t ;
number/=16;
System. out . println (
"The number in hexadecimal is: "
+result ) ;
}
}
Examine the code:
result = remainder+result
. This means that the value of the
character
remainder
will be added at the beginning of the string.
3.6 Summary
The chapter introduced the three loop types in Java:
while
,
do-while
,and
for
.The
two while loops are used when we want to keep repeating the same list of operations until
some event happens. For example, we may want to read input from the keyboard until a
positive number is entered. The difference between the two while loops is that the
do-while
loop guarantees that the body of the loop will be executed at least once. Conversely, if the
condition inside a
while
statement is initially false, then the body of the
while
loop will
never be executed.
The
for
loop is perfect when counting is involved. For example, one can use a
for
loop
to print the numbers from 1 to 10. A
for
loop usually has one or more counter variables
that change after every execution of the body of the loop. When the middle condition of
the
for
loop becomes false, the body of the loop stops repeating and the program continues
from the line that is immediately after the
for
loop.
The chapter also introduces the modulus (a.k.a., remainder) operator. It is used to
calculate the remainder of dividing two integers.
3.7 Syntax
i++;
⇒
Increment
i
by one.
i--;
⇒
Decrement
i
by one.
⇒
Make
a
equal to
i
andthenincrement
i
by one.
a = i++;
