created 05/08/00; edited 11/09/2012, 07/11/2016
Write a program that creates a "personalized" letter, given a form letter and a person's name. The form letter is an input file of text (use file redirection as discussed in chapter 23). The person's name is a command line argument. The file is normal text, but with a * wherever a person's name should be substituted. For example:
Dear *, I have exciting news for you, *!!! For just $49.99 plus postage and handling you, *, can be the proud owner of a genuine leather mouse pad! No more finger strain for you, *, as you surf the web with style. Act Soon, Venture Marketing Corp.
Assume the above is in a file junk.txt
.
A run of the program outputs:
C:\chap49D>java JunkGenerator "Occupant" < junk.txt Dear Occupant, I have exciting news for you, Occupant!!! For just $49.99 plus postage and handling you, Occupant, can be the proud owner of a genuine leather mouse pad! No more finger strain for you, Occupant, as you surf the web with style. Act Soon, Venture Marketing Corp. C:\chap49D>
Write the program so that it will substitute for any number of * on
one line, and accepts any number of lines as input.
The main program loop will be a while
loop that
continues until the input string (read with readLine()
)
is null
.
If you wish to avoid the command line argument, ask the user for the occupant name and input it in the usual way.
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Write a program that reads in a sentence from the user and prints it out with each word reversed, but with the words and punctuation in the original order:
C:\> java reverseSent Input: Go to the main menu. oG ot eht niam unem.
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An International Standard Book Number (ISBN) is a code that uniquely identifies an edition of a book. The ISBN consists of ten digits separated by dashes into groups. The groups are of various sizes, except for the last group. The last group is always a single character, '0' through '9' or 'X', and acts as a check on the rest of the digits.
0-670-03441-X 0-201-48558-3 1-56592-262-X 0-06-027900-1 0-439-45695-9 0-470-84371-3 1-4000-3136-2 0-19-856453-8 1-85671-104-8
The last character is calculated from the other 9 digits:
For example:
0-201-48558-3 0 * 10 = 0 2 * 9 = 18 0 * 8 = 0 1 * 7 = 7 4 * 6 = 24 8 * 5 = 40 5 * 4 = 20 5 * 3 = 15 8 * 2 = 16 ----- sum = 140 140 / 11 = 12 rem 8 11 - 8 = 3 <-- the check digit
Write a program that prompts the user for an ISBN and then checks if the ISBN is correct. Calculate a check character from the first nine digits and compare it to the last character of the ISBN. If the two do not agree, the ISBN is incorrect.
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Modify the program ReverseTester
of the program so that it
includes a method that creates a random string 1000 characters long.
In the main method, reverse that string 1000 times.
Merely call reverse
and then discard the string, done print it out.
(For debugging purposes, start out with 100 reversals of a short string, or something else manageable.)
Time how long this takes. Now change the program so it does the same thing but
with the version of reverse
that uses String
s only.
Time how long that version of the program takes.
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End of Exercises.