Java Reference
In-Depth Information
*8.4
(
Use the
Random
class
) Write a program that creates a
Random
object with seed
1000
and displays the first 50 random integers between
0
and
100
using the
nextInt(100)
method.
*8.5
(
Use the
GregorianCalendar
class
) Java API has the
GregorianCalendar
class
in the
java.util
package, which you can use to obtain the year, month, and day of a
date. The no-arg constructor constructs an instance for the current date, and the meth-
ods
get(GregorianCalendar.YEAR)
,
get(GregorianCalendar.MONTH)
, and
get(GregorianCalendar.DAY_OF_MONTH)
return the year, month, and day.
Write a program to perform two tasks:
Display the current year, month, and day.
■
The
GregorianCalendar
class has the
setTimeInMillis(long)
, which
can be used to set a specified elapsed time since January 1, 1970. Set the value
to
1234567898765L
and display the year, month, and day.
■
Sections 8.7-8.9
**8.6
(
Display calendars
) Rewrite the
PrintCalendar
class in Listing 5.12 to display
calendars in a message dialog box. Since the output is generated from several sta-
tic methods in the class, you may define a static
String
variable
output
for stor-
ing the output and display it in a message dialog box.
8.7
(
The
Account
class
) Design a class named
Account
that contains:
A private
int
data field named
id
for the account (default
0
).
■
A private
double
data field named
balance
for the account (default
0
).
■
A private
double
data field named
annualInterestRate
that stores the
current interest rate (default
0
). Assume all accounts have the same interest rate.
■
A private
Date
data field named
dateCreated
that stores the date when the
account was created.
■
A no-arg constructor that creates a default account.
■
A constructor that creates an account with the specified id and initial balance.
■
The
accessor
and
mutator
methods
for
id
,
balance
,
and
■
annualInterestRate
.
The accessor method for
dateCreated
.
■
A method named
getMonthlyInterestRate()
that returns the monthly
interest rate.
■
A method named
getMonthlyInterest()
that returns the monthly interest.
■
A method named
withdraw
that withdraws a specified amount from the
account.
■
A method named
deposit
that deposits a specified amount to the account.
Draw the UML diagram for the class and then implement the class. (
Hint
: The method
getMonthlyInterest()
is to return monthly interest, not the interest rate. Monthly
interest is
balance * monthlyInterestRate
.
monthlyInterestRate
is
annualInterestRate / 12
. Note that
annualInterestRate
is a percentage,
e.g.,like 4.5%. You need to divide it by 100.)
Write a test program that creates an
Account
object with an account ID of 1122,
a balance of $20,000, and an annual interest rate of 4.5%. Use the
withdraw
method to withdraw $2,500, use the
deposit
method to deposit $3,000, and print
the balance, the monthly interest, and the date when this account was created.
■
8.8
(
The
Fan
class
) Design a class named
Fan
to represent a fan. The class contains:
Three constants named
SLOW
,
MEDIUM
, and
FAST
with the values
1
,
2
, and
3
to
denote the fan speed.
■
VideoNote
The
Fan
class