Question

1. For the second part of the Lab, improve the following Java program with functions. You should look for places in the code where similar statements are repeatedand think about how towrite function(s) to replace those statements. Unlike the first part of the Lab, in this exercise you will probably want to create one or more functions that return a value, and use the returned values in the rest of the program.

This is the Painting.javasource file for you to modify (bluelines are my additions):

public class Painting

{

   public static void main(String[] args)

   {

        double width, length, wallArea, ceilingArea;

        final double HEIGHT = 8;

      

        System.out.println("Calculation of Paint Requirements");

        

        System.out.print("Enter room length: ");

        length = Keyboard.nextDouble();

          // these 2 lines will make a nice function, promptDouble,

          // then replace those 2 lines with this single line:

          // length = promptDouble("Enter room length: ");

        System.out.print("Enter room width: ");

        width = Keyboard.nextDouble();

          // these 2 lines should be replaced in the same way:

          // width = promptDouble("Enter room width: ");

        

        wallArea = 2 * (length + width) * HEIGHT; // ignore doors

          // this line should use a perimeterfunction instead, as in:

          // wallArea = perimeter(length, width) * HEIGHT;

        ceilingArea = length * width;

          // this line should use a new function called area,

          // similar to perimeter, like so:

          // ceilingArea = area(length, width);

        System.out.println("The wall area is " + wallArea +

             " square feet.");

        System.out.println("The ceiling area is " + ceilingArea +

             " square feet.");

   }

}

Your job in this Lab is to write these three functions and make the above changesin the Java program Painting.java.

Answer 1

import java.util.Scanner;

public class Painting {

    public static Scanner Keyboard = new Scanner(System.in);

    public static double promptDouble(String s) {
        System.out.print(s);
        return Keyboard.nextDouble();
    }

    public static double perimeter(double length, double width) {
        return 2 * (length + width);
    }

    public static double area(double length, double width) {
        return length * width;
    }

    public static void main(String[] args) {
        double width, length, wallArea, ceilingArea;
        final double HEIGHT = 8;
        System.out.println("Calculation of Paint Requirements");
        length = promptDouble("Enter room length: ");
        width = promptDouble("Enter room width: ");
        wallArea = perimeter(length, width) * HEIGHT;
        ceilingArea = area(length, width);
        System.out.println("The wall area is " + wallArea + " square feet.");
        System.out.println("The ceiling area is " + ceilingArea + " square feet.");
    }
}