Chapter 5, Problem 6E

a.

Class implementation in java:

Main.java:

//Import package

import java.util.Scanner;

//Define "Main" class

public class Main

{

    //Declare variables in "private" modifiers

    private int number_sold;

    private double totalSales;

    private double totalDiscounts;

    private double cost_per_item;

    private int bulk_quantity;

    private double bulk_dis_percent;

    //Method defintion for set values

    public void setValues(double c, int b, double d)

    {

        //Assign values to given variables

        number_sold = 0;

        totalSales = 0.0;

        totalDiscounts = 0.0;

        cost_per_item = c;

        bulk_quantity = b;

        bulk_dis_percent = d;

    }

    //Method definition for "displaySales"

    public void displaySales()

    {

        //Display given values

System.out.println("Number of items sold: " + number_sold);

System.out.println("Total Sales: " + totalSales);

System.out.println("Total discount: "+totalDiscounts);

    }

    //Method definition for "registerSale"

    public void registerSale(int n)

    {      

        //If "n" is greater than "0", then

        if(n > 0)

        {

//Initializes the basic amount to given formula

            double basic_amount = cost_per_item * n;

            //Initializes given discount to "0"

            double discount_given = 0.0;

            //Increment the number of sold items

            number_sold += n;

/* If "n" is greater than or equal to bulk quality, then */

            if(n >= bulk_quantity)

            {

                //Compute given discount amount

discount_given = basic_amount * bulk_dis_percent / 100;

            }

            //Increment the total sales

totalSales += (basic_amount - discount_given);

            //Increments the total discount values

            totalDiscounts += discount_given;

        }

    }

    //Define main function

    public static void main(String[] args)

    {

        //Create object for "Main" class

        Main sample = new Main();

//Call "setValues" method for object of "Main" class

        sample...

b.

Test class for some Java statement:

//Create object for "Main" class

Main sample = new Main();

//Call "setValues" method for object of "Main" class

sample.setValues(20.0, 20, 100.0);

//Display given message

System.out.println("User are selling 1 piece of some product.");

//Call "registerSale" method with argument of "1"

sample.registerSale(1);

//Call "displaySales" method

sample.displaySales();

//For next line

System.out.println();

//Display given message

System.out.println("User are selling 8 pieces of some product.");

System.out.println("Total should be 9 items, sales: 180.0, discounts: 0.0");

//Call "registerSale" method with argument of "8"

sample.registerSale(8);

//Call "displaySales" method

sample.displaySales();

//For next line

System.out.println();

//Display given message

System.out.println("User are selling 20 pieces of some product.");

System.out.println("Total should be 29 items, sales: 180.0, discounts: 400.0");

//Call "registerSale" method with argument of "20"

sample...