SELECTIONS - Introduction to Java Programming: Comprehensive Version - page 97

3.26

Write a Boolean expression that evaluates to true if weight is greater than
50 pounds or height is greater than 60 inches.

3.27

Write a Boolean expression that evaluates to true if weight is greater than
50 pounds and height is greater than 60 inches.

3.28

Write a Boolean expression that evaluates to true if either weight is greater than
50 pounds or height is greater than 60 inches, but not both.

3.11 Case Study: Determining Leap Year
A year is a leap year if it is divisible by 4 but not by 100 , or if it is divisible by 400 .

Key
Point

You can use the following Boolean expressions to check whether a year is a leap year:

// A leap year is divisible by 4
boolean isLeapYear = (year % 4 == 0 );
// A leap year is divisible by 4 but not by 100
isLeapYear = isLeapYear && (year % 100 != 0 );
// A leap year is divisible by 4 but not by 100 or divisible by 400
isLeapYear = isLeapYear || (year % 400 == 0 );

Or you can combine all these expressions into one like this:

isLeapYear = (year % 4 == 0 && year % 100 != 0 ) || (year % 400 == 0 );

Listing 3.7 gives the program that lets the user enter a year and checks whether it is a leap
year.

L ISTING 3.7

LeapYear.java
1 import java.util.Scanner;
2
3 public class LeapYear {
4 public static void main(String[] args) {
5 // Create a Scanner
6 Scanner input = new Scanner(System.in);
7 System.out.print( "Enter a year: " );
8

int year = input.nextInt(); input

9
10

// Check if the year is a leap year

11 boolean isLeapYear =

leap year?

12 (year % 4 == 0 && year % 100 != 0 ) || (year % 400 == 0 );

13
14 // Display the result
15 System.out.println(year + " is a leap year? " + isLeapYear);
16 }
17 }

display result

Enter a year: 2008
2008 is a leap year? true

Enter a year: 1900
1900 is a leap year? false