Lab Assignment #2: Objects and Strings

Due by 11:59PM on Wednesday, Feb 3.

Reading Assignment

Please do the readings from the book and also read this entire assignment before lab this week!

Getting Started

Comments

/*
Your Name
Your ID Number
Your Username
Which Assignment
Your Laboratory Section Number
*/

Fully document your code with meaningful comments. Use a consistent and readable indentation scheme. You will be graded on both the correctness of your programs and the style in which they are written.

In-Lab Work

This is not a test! If you have any trouble at all with these programs, your AI will be happy to help you!

1. Write a program that prompts the user for a 4 letter word and then prints the word backwards.

   Here's a sample run.

   Enter a four letter word: frog
   
   The word frog is gorf backwards.
   

   Do not worry about what happens if the user enters a word which is longer or shorter than four characters.

   You will need to make use of the substring method in the String class. This function is described on page 68 of the text.

   Save your program as Backwards.java.

2. Write a program that prompts the user for three integer values: a year, a month, and a day. Construct a Time object representing the date given by the user and then print the date one week later.

   Here's a sample run.

   Please enter the year: 1988
   Please enter the month: 2
   Please enter the day: 28
   
   One week after 2/28/1988 is 3/6/1988.
   

   Here's another example:

   Please enter the year: 1987
   Please enter the month: 12
   Please enter the day: 30
   
   One week after 12/30/1997 is 1/6/1998.
   

   Consult the table on page 91 of the text for a handy list of the methods available in the Time class. All of the get methods return an int type value. The addseconds method does not return a value; it actually updates the object itself by changing its internal state. We call such a method a mutator.

   Save your program as Week.java.

Lab Assignment

Please take care to use the exact filenames specified in the problems below.

1. Exercise P2.13, Page 81. Refer to the table on the bottom of page 73 for a synopsis of the important String methods. Save your program in a file named Comma.java.

2. Exercise P2.22, Page 84. Save your program in a file named Months.java.

3. Exercise P3.17, Page 129. Display a nice welcome message to the user with instructions detailing what he is supposed to do. To give the user time to read the instructions, pause by prompting him to press Enter when he is ready to take the typing test. After he has pressed Enter, determine the current time and then read the sentence that he types. Again determine the current time and figure out the number of seconds that have elapsed since the test started. For example,

   Welcome to the Typing Test!
   Please type the following sentence exactly as it appears below.
   
   The quick brown fox jumps over the lazy dog.
   
   Press Enter when you are ready to begin... <user presses Enter here>
   
   Theq uick brown fix jumcs over the laay dog.
   
   Your time: 5 seconds
   
   Good-bye.
   

   Notice that you do not need to count typos. It doesn't really matter what the user types at all.

   Save your program in a file named Typing.java.

Submitting Your Lab Assignment

For this lab, you must submit the two in-lab exercise during your normally scheduled lab session. By Wednesday, February 3 at midninght you should submit these three files:

• Comma.java
• Months.java
• Typing.java

Do not submit .prj or .class files. Only the three files named above should be submitted.

In order to submit files, click on the following link to send mail to:

with the following Subject:

and then Attach your program files to the e-mail message. You may attach all three files in the same message, but you don't have to. You can submit your programs in separate e-mails if you wish. Do not type anything in the body of the message! You must use the filenames specified in this assignment and you must attach the files to the mail message.