Show me the steps to solve Problem $3$: Implementing a Shopping Cart

Implement a simple shopping cart using an array of

objects.

Files Provided:

$-$ : A class to represent an item with name, price, and quantity.

$-$ ShoppingCart.java: A class representing the shopping cart with an array of objects.

Item.java

import java.text.NumberFormat;

public class Item $\backslash \{$

private String name;

private double price;

private int quantity;

$//$

$//$ Create a new item with the given attributes.

$//$

public Item $($String itemName, double itemPrice, int numPurchased$)\backslash \{$

name $=$ itemName;

price $=$ itemPrice;

quantity $=$ numpurchased;

$\backslash \}$

$//$

$//$ Return a string with the information about the item

$//$

public string tostring $()\backslash \{$

NumberFormat fmt $=$ NumberFormat.getCurrencyInstance$()$;

return $($name $+"\backslash$t$"+$ fmt$.$format$($price$)+"\backslash$t$"+$ quantity $+"\backslash$t$"$

$+$ fmt$.$format$($price $*$ quantity$))$;

$\backslash \}$

$//$

$//$ Returns the unit price of the item

$//$

public double getPrice$()\backslash \{$

return price;

$\backslash \}$

$//$

$//$ Returns the name of the item

$//$

public string getName$()\backslash \{$ return name;

$\backslash \}$

$//$

$//$ Returns the quantity of the item

$//$

public int getquantity$()\backslash \{$

return quantity;

ShoppingCart.java

$```$

import java.text.NumberFormat;

$```$

public class ShoppingCart $\{$

private int itemCount; $//$ total number of items in the cart

private double totalprice; $//$ total price of items in the cart

private int capacity; $//$ current cart capacity

$//$

$//$ Creates an empty shopping cart with a capacity of $5$ items.

$//$

public ShoppingCart$()\{$

capacity $=5$;

itemCount $=0$;

totalPrice $=0\mathrm{.}0$;

$\}$

$//$

$//$ Adds an item to the shopping cart.

$//$

public void addToCart$($String itemName, double price, int quantity$)\{$

$//$ Implementation of adding item to cart should go here

$\}$

$//$

$//$ Returns the contents of the cart together with summary information.

$//$

public string toString$()\{$

NumberFormat fmt $=$ NumberFormat.getCurrencyInstance$()$;

string contents $="$

shopping Cart

$"$;

contents $+="$

Item$\backslash$t$\backslash$tUnit Price$\backslash$tQuantity$\backslash$tTotal

$"$;

for $($int i $=0$; i $$ itemCount; i$++)$

contents $+=$ cart$[$i$].$tostring$()+"$

$"$; $```$

contents $+="$

Total Price: $"+$ fmt$.$format$($totalPrice$)$;

contents $+="$

$"$;

return contents;

$\}$

$//$

$//$ Increases the capacity of the shopping cart by $3$

$//$

private void increaseSize$()\{$

$//$ Implementation of increasing the cart size should go here

$```$

Instructions:

$1.$ In $,$ declare an array of Item objects and initialize it with a capacity of $5.$

$2.$ Implement to expand the cart's capacity by $3$ if more space is needed.

$3.$ Implement to add items to the cart and update the total price.

Example:

$-$ Input:

Name: Pen, Price: $1\mathrm{.}5,$ Quantity: $2$

$-$ Output:

The file contains a program to test the variable length method average from Section $7\mathrm{.}5$ of the text. Note that average must be a static method since it is called from the static method main. Write a program to test variable$-$length parameter lists.

Parameters.java

import java.util.scanner;

public class Parameters

$//$ Calls the average and minimum methods with

$//$ different numbers of parameters.

public static void main$($String$[]$ args$)\backslash \{$

double mean$1,$ mean$2$;

mean $\backslash (1=\backslash )$ average $\backslash ((42,69,37)\backslash )$;

mean$2\backslash (=\backslash )$ average$(\backslash (35,43,93,23,40,21,75)\backslash )$;

System.out.println$("$mean$1="+$ mean$1)$;

system.out.println$("$mean$2="+$ mean$2)$;

$3$

$//$ Returns the average of its parameters.

public static double average $($int $...$ list$)\backslash \{$

double result $\backslash (=0\mathrm{.}0\backslash )$;

if $($list$.$ length $!=0)\backslash \{$

int sum $\backslash (=0\backslash )$;

for $($int num : list$)$

sum $\backslash (+=\backslash )$ num;

result $\backslash (=\backslash )($double$)$ sum $/$ list.length;

$3$

return result;

$3$

$(3)$ Steps:

$1.$ Implement a method that calculates the average of any number of integer arguments.

$2.$ Test the method with different sets of arguments, including a single integer and an empty parameter list.

$3.$ Add an interactive part that accepts a series of nonnegative integers $($up to $20)$ from the user and stops when a negative number is entered.

$4.$ Add a method that finds the minimum value in the passed parameters and use it to test each set of arguments.

Instructions:

$-$ Input:

$-$ Output:

Mean: $8\mathrm{.}5$

Minimum: $4$