PROJECT    OOP in Java – Stock Transactions  Solution

Objective Inheritance example.


Create stock transactions for XYZ stock for various clients and display a gain or loss on shares based on a given transacted stock price versus an updated stock price.

Steps to Complete this Project

STEP 1 Create 2 files in Eclipse under a project named Inheritance.

Enter code as follows for your first file called

import java.text.DecimalFormat;

import java.util.Scanner;


* The Stock class holds data about a stock.

* This version of the class has an equals method.


public class Stock


private String symbol; // Trading symbol of stock

private static double sharePrice; // Current price per share

static int count=0;



@param sym The stock's trading symbol.

@param price The stock's share price.


public Stock(String sym, double price)


symbol = sym;

sharePrice = price;


public Stock() //for Subclass call



System.out.println("New client request count #" + count);



Copy constructor

@param object2 The Stock object to copy.


public Stock(Stock object2)


this.symbol = object2.symbol;

this.sharePrice = object2.sharePrice;



getSymbol method

@return The stock's trading symbol.


public String getSymbol()


return symbol;



getSharePrice method

@return The stock's share price


public double getSharePrice()


return sharePrice;



toString method

@return A string indicating the object's

trading symbol and share price.


public String toString()


// Create a string describing the stock.

String str = "Trading symbol: " + symbol +

"\nShare price: " + sharePrice;

// Return the string.

return str;



The copy method makes a copy of a Stock object.

@return A reference to a copy of the calling object.


public Stock copy()


// Create a new Stock object and initialize it

// with the same data held by the calling object.

Stock copyObject = new Stock(symbol, sharePrice);

// Return a reference to the new object.

return copyObject;


public static void main(String[] args)


int sharesToBuy; // Number of shares to buy.

// Create a Stock object for the company stock.

// The trading symbol is XYZ and the stock is

// currently $9.62 per share.

Stock xyzCompany = new Stock("XYZ", 9.62);


// Create a Scanner object for keyboard input.

Scanner keyboard = new Scanner(;

// Create a DecimalFormat object to format numbers

// as dollar amounts.

DecimalFormat dollar = new DecimalFormat("#,###.00");

//StockPurchase array of buyers

StockPurchase [] theBuyers = new StockPurchase[3];

for(int x=0;x<3;x++)


// Display the current share prices.

System.out.println("XYZ Company's stock is currently $"

+ dollar.format(xyzCompany.getSharePrice())

+ " per share.");

// Get the number of shares to purchase.

System.out.print("How many shares do you want to buy? ");

sharesToBuy = keyboard.nextInt();

theBuyers[x]= new StockPurchase(xyzCompany, sharesToBuy);

// Display the cost of the transaction.

System.out.println("Cost of the stock: $"

+ dollar.format(theBuyers[x].getCost()));


}//end main

}//end class

Next enter code as follows for your second file called

public class StockPurchase extends Stock


private Stock stock; // The stock that was purchased

private int shares; // Number of shares owned



@param stockObject The stock to purchase.

@param numShares The number of shares.


public StockPurchase(Stock stockObject, int numShares)


// Create a copy of the object referenced by

// stockObject.

super(); //call base class constructor

stock = new Stock(stockObject); //call copy constructor

shares = numShares;



getStock method

@return A copy of the Stock object for the stock

being purchased.


public Stock getStock()


// Return a copy of the object referenced by stock.

return new Stock(stock);



getShares method

@return The number of shares being purchased.


public int getShares()


return shares;



getCost method

@return The cost of the stock purchase.


public double getCost()


return shares * stock.getSharePrice();



STEP 2 Run and test your code with the following input values 1, 2 & 3 when prompted

via the supplied for loop.

Your display should look exactly like the snapshot below.

STEP 3 Modify your code to display each client by number, their original stock cost and

a gain or loss on shares based on an updated stock price of $20/share. Your

outcome should be presented in a table style format similar to the snapshot shown below when you rerun your app.

Tweak any code necessary to add in extra fields, plus any additive variables, functions, etc., you deem necessary to your class, primarily your Stock class, to allow for a stock price update and a client Number to track.

To display a gain or loss on transactions after the stock price has been updated, you want to show the change in stock prices * number of shares purchased per client.



Check the coding logic and use the functions given especially to help derive at your


Sample final run follows…

Sample final run

STEP 4 Turn in your code for the and files and a snapshot of your input and displays as shown above for full credit into Blackboard.
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