I just wrote my first program using methods (I am only on chapter 5). I am not sure where I would use javadocs other than the ones that I already have in my code. Can someone help me?
/**
* @author Brock Shelton
* Date: March 15, 2010
* purpose: Complete a program that asks the user to enter the length
* and width and then determine the area and display it to the screen.
**/
import javax.swing.JOptionPane; // imports the JOptionPane class
public class AreaRectangle
{ // start of the class
/**
*
* @param the args default argument for the main method
*
*/
public static void main(String[] args)
{ // begins main
double length; // The rectangle's length
double width; // The rectangle's width
double area; // The rectangle's area
displayWelcome(); // calls the displayWelcome message
// Get the rectangle's length from the user.
length = getLength();
// Get the rectangle's width from the user.
width = getWidth();
// Get the rectangle's area.
area = getArea(length, width);
// Display the rectangle data.
displayData(length, width, area);
}
public static double getLength()
{ // start of the getLength method
String input; // declares input as a string
double length = 0.0; // declares length as a double and sets it to 0
final String ASK = "Whats the rectangle's length?"; // declares a constant to ask the user
final String INVALID = " You have entered invalid length"; // declares a constant
final String NUM_INVALID = " Length must be positive"; // declares a constant
input = JOptionPane.showInputDialog(ASK); // asks the user for length
try
{ // begin try
length = Double.parseDouble(input); // sets length to the input
} // end try
catch (Exception ex) // exception handler
{
JOptionPane.showMessageDialog(null, INVALID);
System.exit(1); // exits if there is an error
}
if (length <= 0.0)
{ // begins if statement
JOptionPane.showMessageDialog(null, NUM_INVALID);
System.exit(1); /// exits the program if a negative number is entered
} // ends if statement
return length;
} // ends length
public static double getWidth()
{ // begins getWidth method
String input; // declares input as a string
double width = 0.0; // declares width as a double and sets it to 0
final String ASK_2 = " What is the rectangle's width"; // constant to ask the user
final String INVALID_2 = " You have entered invalid width"; // constant to hold invalid input
final String NUM_INVALID = " The width must be positive"; // constant to hold invalid input
input = JOptionPane.showInputDialog(ASK_2); // asks the user to enter width
try
{ // begins try
width = Double.parseDouble(input); // turns input to a double
} // ends try
catch (Exception ex) // exception handler
{ // begins catch
JOptionPane.showMessageDialog(null, INVALID_2); // error message
System.exit(1); // exits if the user enteres characters
} // ends catch
if (width <= 0.0)
{ // begins if statement
JOptionPane.showMessageDialog(null, NUM_INVALID); // error message
System.exit(1); // exits if any negative number is entered
} // ends if statement
return width;
}
public static double getArea(double length, double width)
{ // begins getArea
double area; // declares area as a double
area = length * width; // formula for the area
return area;
} // ends getArea
// OUTPUT SECTION
public static void displayData(double length, double width, double area)
{
JOptionPane.showMessageDialog(null, String.format("Length of rectangle = %.2f\n" +
"Width of rectangle = %.2f\n" +
"Area of rectangle = %.2f", length, width, area)); // displays the length, width, and area
}
public static void displayWelcome()
{
final String WELCOME = " Author: Brock Shelton \n"
+ " Date: March 15, 2010 \n"
+ " Purpose: finish a program that asks the user to input width and length \n"
+ " and then determins the area of the rectangle."; // string holding welcome message
JOptionPane.showMessageDialog(null, WELCOME); // displays welcome message
}
}