1. Introduction to Programming
Java Lab 6:
if Statement
JavaLab6 lecture slides.ppt
Ping Brennan
15 February 2013

2. Java Project
Project Name: JavaLab6
QuizGrading
LeapYear

3. Class QuizGrading
Reads in an integer (from the keyboard) as the score.
Displays the grade assigned to the score according to the following table:
Objectives
Understand the use of multiple if statements (if-else statements).
Applying relational operators: < , <= , >=
Score
Grade A
80 – 89 B C
60 – 69 D
< 60 E

4. Class QuizGrading (2) Method Applying
Read a numeric input (i.e. score) from the keyboard.
char grade = ' '; // Java type char
if (score >= 90)
{ grade = 'A'; }
else if (score >= 80)
{ grade = 'B'; }
else if /* To Do – write similar if–else statements to check the score
for grades ‘C’, ‘D’ and ‘E’. */

5. Anatomy of Class QuizGrading
import java.util.Scanner;
public class QuizGrading {
public static void main(String[] args)
/* To Do - write code to read score from the
key board which is an integer of type int. */
char grade = ' ';
if (score >= 90)
{ grade = 'A'; }
else if (score >= 80)
{ grade = 'B'; }
else if // To Do - write similar Java if-else statements
// Lastly, print the grade, along with an appropriate description }

6. Class LeapYear
Reads in a year and computes whether the year is a leap year.
Objectives
Understand the use of if-else statement
Applying the arithmetic operator % (computes the remainder of an integer division)
Using relational operators: == , !=
Using boolean operators: && , ||

7. Class LeapYear (2) Formulae Applying
Read year input from keyboard using Scanner class
if a year is divisible by 4 but not by 100, it is a leap year.
if a year is divisible by 4 and by 100, it is not a leap year unless it is also divisible by 400.
boolean a = (year % 4) == 0; // divisible by 4
boolean b = (year % 100) != 0; // not by 100
boolean c = ( (year % 100) == 0 ) // divisible by 100
&& ( (year % 400) == 0 ); //and divisible by 400
Use the boolean expression: ( a && ( b || c) ) to find a leap year.

8. Anatomy of Class LeapYear
import java.util.Scanner;
public class LeapYear {
public static void main(String[] args)
/* To Do:
(i) declare a variable year of type int
(ii) read a numeric input (year) from the keyboard */
/* declare the boolean variables a, b and c as
shown in slide 7 */
/* write an if-else statement and use the boolean
expression shown in slide 7 */
/* write a println statement to display the result
of the computation. */ }

9. Flow Chart for if-else statement [back to slide 4]
start
score >= 90
true
false
score >= 80
grade = ‘A’
true
false
grade = ‘B’
true
score >= 70
false
grade = ‘C’
more if-else statements
Print statement