CONTROL STRUCTURES I: SELECTION - Java Programming: From Problem Analysis to Program Design - page 191

Next, we give various examples to show how an if statement works. We also show some
common syntax and/or semantic errors that beginning programmers often make.

EXAMPLE 4-6

if (score >= 90)
grade = 'A';
In this code, if the logical expression, score >= 90 , evaluates to true , the assignment
statement, grade = 'A'; , executes. If score >= 90 evaluates to false , the assignment
statement, grade = 'A'; , is skipped. For example, if the value of score is 95 , the value
assigned to the variable grade is A .

4

EXAMPLE 4-7

The following Java program finds the absolute value of an integer.
//Program to determine the absolute value of an integer.

import javax.swing.JOptionPane;

public class AbsoluteValue
{

public static void main(String[] args)
{

int number;
int temp;

String numString;

numString =
JOptionPane.showInputDialog("Enter an integer:"); //Line 1

number = Integer.parseInt(numString); //Line 2

temp = number; //Line 3

if (number < 0) //Line 4

number = -number; //Line 5

JOptionPane.showMessageDialog( null ,
"The absolute value of " + temp
+ " is " + number,
"Absolute Value",
JOptionPane.INFORMATION_MESSAGE); //Line 6

System.exit(0);

}

}