Background ! Assign ! ment 3 ! Stock trading is done using a so-called double au
ID: 674344 • Letter: B
Question
Background!
Assign!ment 3!
Stock trading is done using a so-called double auction system in which buyers and sellers can enter competitive orders simultaneously. The orders are of the form "buy m shares at $x each" or "sell n shares at $y each". Since the number of orders is very large, a computer program must be used to continuously match orders and to store unmatched orders for subsequent processing. In this project you are asked to write a Java program performing order matching according to the rules of a double auction system.
The double action system operates as follows. When a new buy order of $x per share arrives, it is simply stored for future use if none of the stored sell orders has an asking price lower than or equal to $x per share. If at least one of the stored sell orders has an asking price of $x per share or less, then the new buy order is matched with the sell order with the lowest asking price. When two or more of the stored sell orders have lowest asking price, then the earliest sell order must be matched first. If some shares of the sell order with lowest asking price remain unmatched, they must be saved for future possible matchings. On the other hand, if some shares of the new buy order remain unmatched, the above matching algorithm is repeated until no more matches can be made.
Processing of a new sell order with an asking price of $y per share is done in a similar way. If all stored buy orders have an offer price per share strictly lower than $y per share, then no matches can be made and the new order is simply stored for possible future matches. Otherwise, the new sell order is repeatedly matched with the buy order with the highest offer price until no more matches are possible, handling ties and partial matches as above.
Implementation requirements!
You may either use the priority queue classes provided by the Java API or implement your own. However, to receive full credit, your program should meet the efficiency requirements in problem C-8.2 of the textbook, i.e., should require O(logn) time per order when processing a list of n orders.
Program Input!
Your program should read from the standard input a list of buy and sell orders in the format given in the samples below, with one order per line.
Program Output!
The program must print to the standard output the total number and the total value of exchanged shares (i.e., total amount paid by buyers). Use the format given in the examples below, and follow the output with a new line. (Note that after processing the input there can be orders or portions of orders left uncleared.)
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Sample Input 1
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Output for Sample Input 1
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Sample Input 2
sell 50 shares at 30 each! buy 100 shares at 20 each! buy 40 shares at 40 each! sell 50 shares at 10 each! buy 30 shares at 30 each! !
Output for Sample Input 2
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Explanation / Answer
public static void main(String args[]) { // Create an array list for order to read data from the file ArrayList orders = new ArrayList(); // Create sell and buys array list to get the list of // buyers and sellers ArrayList sells = new ArrayList(); ArrayList buys = new ArrayList(); // declare the required variables int price = 0; int exchange = 0; // since we are using files put the execution code in try..catch // block try { // create a file object by passing it to scanner class // to read the file data Scanner input = new Scanner(System.in); // read the lines from the text file while (input.hasNextLine()) { orders.add(input.nextLine()); } // separate the orders for (int i = 0; iRelated Questions
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