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
 
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