SELECTIONS - Introduction to Java Programming: Comprehensive Version - page 110

*3.8

( Sort three integers ) Write a program that prompts the user to enter three integers
and display the integers in non-decreasing order.

VideoNote

**3.9

( Business: check ISBN-10 ) An ISBN-10 (International Standard Book Number)
consists of 10 digits: d 1 d 2 d 3 d 4 d 5 d 6 d 7 d 8 d 9 d 10 . The last digit, d 10 , is a checksum,
which is calculated from the other nine digits using the following formula:

Sort three integers

( d 1 * 1 + d 2 * 2 + d 3 * 3 + d 4 * 4 + d 5 * 5 +

d 6 * 6 + d 7 * 7 + d 8 * 8 + d 9 * 9) % 11

If the checksum is 10 , the last digit is denoted as X according to the ISBN-10
convention. Write a program that prompts the user to enter the first 9 digits and
displays the 10-digit ISBN (including leading zeros). Your program should read
the input as an integer. Here are sample runs:

Enter the first 9 digits of an ISBN as integer: 013601267
The ISBN-10 number is 0136012671

Enter the first 9 digits of an ISBN as integer: 013031997
The ISBN-10 number is 013031997X

3.10 ( Game: addition quiz ) Listing 3.3, SubtractionQuiz.java, randomly generates a
subtraction question. Revise the program to randomly generate an addition ques-
tion with two integers less than 100.
Sections 3.8-3.16
*3.11

( Find the number of days in a month ) Write a program that prompts the user
to enter the month and year and displays the number of days in the month. For
example, if the user entered month 2 and year 2012 , the program should display
that February 2012 had 29 days. If the user entered month 3 and year 2015 , the
program should display that March 2015 had 31 days.

3.12

( Palindrome number ) Write a program that prompts the user to enter a three-digit
integer and determines whether it is a palindrome number. A number is palin-
drome if it reads the same from right to left and from left to right. Here is a sample
run of this program:

Enter a three-digit integer: 121
121 is a palindrome

Enter a three-digit integer: 123
123 is not a palindrome

*3.13

( Financial application: compute taxes ) Listing 3.5, ComputeTax.java, gives the
source code to compute taxes for single filers. Complete Listing 3.5 to compute
the taxes for all filing statuses.

3.14

( Game: heads or tails ) Write a program that lets the user guess whether the flip of
a coin results in heads or tails. The program randomly generates an integer 0 or 1 ,
which represents head or tail. The program prompts the user to enter a guess and
reports whether the guess is correct or incorrect.