Describe how the Liskov Substitution Principle can influence the way that you might implement the Open Closed Principle in software. (Describe how it might help but also how it might constrain implementations of the OCP.)

Please SOLVE EXERCISE 4.20

Programming Exercise 3.20 required you to design a PID manager that allocated a unique process identifier to each process.

Exercise 4.20 requires you to modify your solution from Exercise 3.20 by writing a program that creates a number of threads that requested and released process identifiers. Modify your solution to Exercise 4.20 by ensuring that the data structure used to represent the availability of process identifiers is safe from race conditions. Use Pthreads mutex locks.

Please SOLVE EXERCISE 4.20

My Programming Exercise 3.20)  

package com.company;

import java.util.HashMap;

/*

dip manager manages process identifiers, which are unique.

Several active processes can not have same pid.

It creates unique pid, which is assigned to ti.

When process completes execution pid is returned to pdd manager.

pdd manager reassigns this pid.

--first method:

  creates and initializes the map in order to maintain the list of available pids.

--second method:

  finds next avialable pid and assigns them to active processes

--third method:

  releases old identifiers by making them available again for new processes.

*/

public class PID_MAP {

    /*

    Variables that will specify the range of pid values

    basically it says that process identifiers are constant

    integers (final key word) between 300 and 500.

    */

    public static final Integer MIN_PID = 300;

    public static final Integer MAX_PID = 5000;

    /*

    variables that identify availability of a particular process identifier

    with 0 being available and 1 being currently in use

    */

    public Integer available = 0;

    public Integer notAvailable = 1;

    /*

    I decided to use hash map data structure named PID_map to represent the availability of process identifiers with Key/Value principle

     */

    public HashMap PID_map;

    /*

     int allocate_map(void) - Creates and initializes a data structure for representing pids; returns -1 if unsuccessful and 1 if successful

     This method allocates a hash map of possible pid-s.

     The map has Key/Value principle.

     Key is an Integer, Value is "available (0) /not available (1)" for allocation to an active process.

     */

    public int allocate_map(){

        //allocated map for certain capacity

        PID_map = new HashMap(MAX_PID - MIN_PID + 1); //checks if system has enough resources to allocate a map of the capacity mentioned above

        if(true) {

            for (int i = MIN_PID; i <= MAX_PID; i++) {

                PID_map.put(i, available); //values for all the keys are set to 0, because non of the process will be active if I do not allocate the map first.

            }

        }

        else {

            return -1; //if returns integer "-1" means hash map did not created, initialized and allocated successfully.

        }

        return 1; //if returns integer "1" means hash map successfully created, initialized and allocated.

    }

    /*Process Synchronization means sharing system resources by processes in a such a way that, Concurrent access to shared data is handled thereby minimizing

    the chance of inconsistent data. Thats why we use key word Synchronized.

    */

    /*

    int allocate_pid(void) - Allocates and returns a pid; returns -1 if if unable to allocate a pid (all pids are in use)

     */

    public int allocate_pid(){

        for (Integer i = MIN_PID; i <= MAX_PID; i++){ //traverses through the map to find available pid

            if (PID_map.get(i).equals(available)){ //once the available process identifier is found

                PID_map.put(i,notAvailable); //the process identifier is updated from avialeble to unavialable

                return i; //returns the "new unavailable pid"

            }

        }

        return -1; //returs -1 if all process identifiers are in use.

    }

    /*

    void release_pid(int_pid) - Releases a pid.

     */

    public void release_pid(Integer k){ // method releases used process identifier which is passes as parameter-Integer K

        if(k > MAX_PID || k < MIN_PID){ //double checks if Pid is valid

            System.out.println("Error! not valid identifier"); //if not system notifies that its invalid process identifier

        }

        PID_map.put(k,available); //if it is valid pid, it becomes released and the pid can be used by another process. It is set to available (0)

    }

}

/*

DELETED key word SYNCHRONIZED for acllocate_pid() and release_pid() functions

*/

Write a program that will search through an array and check to see if the first number in the array occurs more than once. If the first number occurs more than once, return true. Otherwise, return false. If the array is empty, return false?

You will need to use a variable, loop, and if statement.

Explain why some people might say that "generalisation" in software design (i.e. designing software so that it can anticipate future evolution) is a "bad smell" (i.e. something that needs to be refactored away)? In your explanation consider arguments for and against generalisation being a “bad smell”.

python programming

• Appropriate and well constructed while and/or for loops (as necessary). • Appropriate if, if-else, if-elif-else statements (as necessary). • The use of the ord() and chr() functions (as necessary). • The following three functions (refer to stage 6 for description): o display_details() o get_menu_choice() o get_offset() • Output that strictly adheres to the assignment specifications. If you are not sure about these details, you should check with the ‘Sample Output – Part II’ provided at the end of this document. • Good programming practice: o Consistent commenting, layout and indentation. You are to provide comments to describe: your details, program description, all variable definitions, and significant sections of code. o Meaningful variable names. • Your solutions MAY make use of the following built-in functions and methods: o Any of the Python built-in functions… specifically, you may find you may need the following: int(), input(), print(), range(), ord(),and chr(). • Your solutions MAY ALSO make use of the following: o Concatenation (+) operator to create/build new strings. o Access the individual elements in a string with an index (one element only). i.e. string_name[index]. o Your own (user-defined) functions (in addition to the three functions listed above). Your solutions MUST NOT use: • break, or continue statements in your solution. Do not use the quit() or exit() functions or the break or return statements (or any other techniques) as a way to break out of loops. Doing so will result in a significant mark deduction.

Sample output

*** Menu ***

1. Encrypt string

2. Decrypt string

3. Brute force decryption

4. Quit

What would you like to do [1,2,3,4]? 1

Please enter string to encrypt: Elvis has left the building!

Please enter offset value (1 to 94): 3

Encrypted string: Hoylv#kdv#ohiw#wkh#exloglqj$

*** Menu ***

1. Encrypt string

2. Decrypt string

3. Brute force decryption

4. Quit What would you like to do [1,2,3,4]? 2

Please enter string to decrypt: Hoylv#kdv#ohiw#wkh#exloglqj$ Please enter offset value (1 to 94): 3

Decrypted string: Elvis has left the building!

*** Menu ***

1. Encrypt string

2. Decrypt string

3. Brute force decryption

4. Quit What would you like to do [1,2,3,4]? 3

Please enter string to decrypt: Hoylv#kdv#ohiw#wkh#exloglqj$

Offset: 1 = Decrypted string: Gnxku"jcu"nghv"vjg"dwknfkpi# Offset: 2 = Decrypted string: Fmwjt!ibt!mfgu!uif!cvjmejoh" Offset: 3 = Decrypted string: Elvis has left the building! Offset: 4 = Decrypted string: Dkuhr~g`r~kdes~sgd~athkchmf Offset: 5 = Decrypted string: Cjtgq}f_q}jcdr}rfc}`sgjbgle~ Offset: 6 = Decrypted string: Bisfp|e^p|ibcq|qeb|_rfiafkd} Offset: 7 = Decrypted string: Ahreo{d]o{habp{pda{^qeh`ejc| Offset: 8 = Decrypted string: @gqdnzc\nzg`aozoc`z]pdg_dib{ Offset: 9 = Decrypted string: ?fpcmyb[myf_`nynb_y\ocf^chaz Offset: 10 = Decrypted string: >eoblxaZlxe^_mxma^x[nbe]bg`y Offset: 11 = Decrypted string: =dnakw`Ykwd]^lwl`]wZmad\af_x Offset: 12 = Decrypted string: P\IBCQ\QEB\?RFIAFKD] Offset: 39 = Decrypted string: !HREO[D=O[HABP[PDA[>QEH@EJC\ Offset: 40 = Decrypted string: GQDNZCCHAZ Offset: 42 = Decrypted string: }EOBLXA:LXE>?MXMA>X;NBE=BG@Y Offset: 43 = Decrypted string: |DNAKW@9KWD=>LWL@=W:MADW Offset: 45 = Decrypted string: zBL?IU>7IUB;;U8K?B:?D=V Offset: 46 = Decrypted string: yAK>HT=6HTA:;ITI=:T7J>A9>CH;EQ:3EQ>78FQF:7Q4G;>6;@9R Offset: 50 = Decrypted string: u=G:DP92DP=67EPE96P3F:=5:?8Q Offset: 51 = Decrypted string: t7P Offset: 52 = Decrypted string: s;E8BN70BN;45CNC74N1D8;38=6O Offset: 53 = Decrypted string: r:D7AM6/AM:34BMB63M0C7:27<5N Offset: 54 = Decrypted string: q9C6@L5.@L923ALA52L/B6916;4M Offset: 55 = Decrypted string: p8B5?K4-?K812@[email protected]:3L Offset: 56 = Decrypted string: o7A4>J3,>J701?J?30J-@47/492K Offset: 57 = Decrypted string: n6@3=I2+=I6/0>I>2/I,?36.381J Offset: 58 = Decrypted string: m5?2

25-270I Offset: 59 = Decrypted string: l4>1;G0);G4-.' 2>+$%3>3'$>!4(+#(-&? Offset: 69 = Decrypted string: b*4'1=&~1=*#$2=2= 3'*"',%> Offset: 70 = Decrypted string: a)3&0<%}0<)"#1<1%"<~2&)!&+$= Offset: 71 = Decrypted string: `(2%/;$|/;(!"0;0$!;}1%( %*#< Offset: 72 = Decrypted string: _'1$.:#{.:' !/:/# :|0$'~$)"; Offset: 73 = Decrypted string: ^&0#-9"z-9&~ .9."~9{/#&}#(!: Offset: 74 = Decrypted string: ]%/",8!y,8%}~-8-!}8z."%|"' 9 Offset: 75 = Decrypted string: \$.!+7 x+7$|},7, |7y-!${!&~8 Offset: 76 = Decrypted string: [#- *6~w*6#{|+6+~{6x, #z %}7 Offset: 77 = Decrypted string: Z",~)5}v)5"z{*5*}z5w+~"y~$|6 Offset: 78 = Decrypted string: Y!+}(4|u(4!yz)4)|y4v*}!x}#{5 Offset: 79 = Decrypted string: X *|'3{t'3 xy(3({x3u)| w|"z4 Offset: 80 = Decrypted string: W~){&2zs&2~wx'2'zw2t({~v{!y3 Offset: 81 = Decrypted string: V}(z%1yr%1}vw&1&yv1s'z}uz x2 Offset: 82 = Decrypted string: U|'y$0xq$0|uv%0%xu0r&y|ty~w1 Offset: 83 = Decrypted string: T{&x#/wp#/{tu$/$wt/q%x{sx}v0 Offset: 84 = Decrypted string: Sz%w".vo".zst#.#vs.p$wzrw|u/ Offset: 85 = Decrypted string: Ry$v!-un!-yrs"-"ur-o#vyqv{t. Offset: 86 = Decrypted string: Qx#u ,tm ,xqr!,!tq,n"uxpuzs- Offset: 87 = Decrypted string: Pw"t~+sl~+wpq + sp+m!twotyr, Offset: 88 = Decrypted string: Ov!s}*rk}*vop~*~ro*l svnsxq+ Offset: 89 = Decrypted string: Nu r|)qj|)uno})}qn)k~rumrwp* Offset: 90 = Decrypted string: Mt~q{(pi{(tmn|(|pm(j}qtlqvo) Offset: 91 = Decrypted string: Ls}pz'ohz'slm{'{ol'i|pskpun( Offset: 92 = Decrypted string: Kr|oy&ngy&rklz&znk&h{orjotm' Offset: 93 = Decrypted string: Jq{nx%mfx%qjky%ymj%gznqinsl& Offset: 94 = Decrypted string: Ipzmw$lew$pijx$xli$fymphmrk%

*** Menu ***

1. Encrypt string

2. Decrypt string

3. Brute force decryption

4. Quit What would you like to do [1,2,3,4]? 4 Goodbye.

Note: Your program must work with the printable ASCII character set. That is, all the characters from ASCII 32 (Space) to ASCII 126 (~). When the offset points to a character beyond 126 it should wrap around to the beginning of the set.

Homework Assignment 4 Instructions: Class name must be: HW4_yourName For example: Michael will name the class of homework assignment 4 as HW4_Michael Grading Rubric: Code running and as per the required conditions and giving expected output = 10 points File named as per instructions = 1 point Comments in code = 4 points Problem: Average calculation for a list Write a program that reads a text file named test_scores.txt to read the name of the student and his/her scores for 3 tests. The program should display class average for first test (average of scores of test 1) and average (average of 3 tests) for each student. Expected Output: ['John', '25', '26', '27'] ['Michael', '24', '28', '29'] ['Adelle', '23', '24', '20'] [['John', '25', '26', '27'], ['Michael', '24', '28', '29'], ['Adelle', '23', '24', '20']] Class average for test 1 is: 24.0 Average for student John is 26.00 Average for student Michael is 27.00 Average for student Adelle is 22.33

Implement C++ program for each of the following.
Let D = [-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36] Each answer is either True or False. If False, give example
of number(s) that make it False. i.e. The Counterexample. ∀x∈D, if x is odd then x > 0
Let D = [-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36] Each answer is either True or False. If False, give example
of number(s) that make it False. i.e. The Counterexample. ∀x∈D, if x is less than 0 then x is even.
Let D = [-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36] Each answer is either True or False. If False, give example
of number(s) that make it False. i.e. The Counterexample. ∀x∈D, if x is even then x <= 0;
Let D = [-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36] Each answer is either True or False. If False, give example
of number(s) that make it False. i.e. The Counterexample. ∀x∈D, if the ones digit of x is 2, then the tens
digit is 3 or 4.
Let D = [-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36] Each answer is either True or False. If False, give example
of number(s) that make it False. i.e. The Counterexample. ∀x∈D, if the ones digit of x is 6, then the tens
digit is 1 or 2.

Recursion.

Question 1

1.1 What are the 2 main components of a recursive function?

1.2 What is more efficient: an explicit loop structure or a recursive function? Explain your answer.

1.3 In what scenarios should a recursive solution be preferred to an iterative solution?

Write a program that has a function (named getNumStats()) that will return a string that has stats on the number entered.

The prototype is:

string getNumStats(double);

The stats are:

            Is the number an integer or a double?

            The polarity (is it positive or negative; 0 counts as positive)

            The parity (is it odd or even)

            Is it a prime number? (for this program, 1 is considered a prime number)

For example, if the following lines of code are executed

double dNum = 14.06;

string test = getNumStats(dNum)

cout << test << endl;

The output that appears on the screen will be:

14.06 is a double

It is positive

It does not have parity

It is not a prime number

Another run is:

double dNum = -27.371;

string test = getNumStats(dNum)

cout << test << endl;

The output that appears on the screen will be:

-23.371 is a double

It is negative

It does not have parity

It is not a prime number

Note: your first line of output may or may not show trailing zeros. You may add that feature to always show zeros (even if the number is an integer)

How can I analyze "Enron Dataset" using ONLY "Naive Bayes model" or "SVM(Support Vector Machine) model" or "Decision Trees model" or  "Random Forest model" or "K Nearest Neighbors model". And for what purpose the result can be used? Please give me some rough ideas and methods. No need to right down the Python codes.

Explain the similarities and differences between Drop (a table), Truncate (the data), and Delete (the data).

I created a shoppingcart program but I'm getting a few compilation failed errors:

1) Tests that ItemToPurchase("Bottled Water", "Deer Park, 12 oz.", 1, 10) correctly initializes item compilation failed

2) Tests default constructor and accessors for ShoppingCart Compilation failed

3)Tests ShoppingCart("John Doe", "February 1, 2016") correctly initializes cart Compilation failed

4) Tests that getNumItemsInCart() returns 6 (ShoppingCart) compilation failed

5) Test that getCostOfCart() returns 9 (ShoppingCart) compilation failed

Complete program:

itemtopurchase.java

public class ItemToPurchase {
// instance variables
private String itemName;
private String itemDescription;
private int itemPrice;
private int itemQuantity;
// default constructor
public ItemToPurchase() {
this.itemName = "none";
this.itemDescription = "none";
this.itemPrice = 0;
this.itemQuantity = 0;
}
public ItemToPurchase(String itemName, int itemPrice, int itemQuantity,String itemDescription) {
this.itemName = itemName;
this.itemDescription = itemDescription;
this.itemPrice = itemPrice;
this.itemQuantity = itemQuantity;
}
// method to set name of the item
public void setName(String name) {
itemName = name;
}
// method to set price of the item
public void setPrice(int price) {
itemPrice = price;
}
// method to set quantity of the item
public void setQuantity(int quantity) {
itemQuantity = quantity;
}
public void setDescription(String description) {
itemDescription = description;
}
// method to get name of the item
public String getName() {
return itemName;
}
// method to get price of the item
public int getPrice() {
return itemPrice;
}
// method to get quantity of the item
public int getQuantity() {
return itemQuantity;
}
public String getDescription() {
return itemDescription;
}
public void printItemPurchase() {
System.out.println(itemName + " " + itemQuantity + " @ $" + itemPrice + " = $" + (itemPrice * itemQuantity));
}
public void printItemDescription() {

System.out.println(itemName+": "+itemDescription);
}
}

shoppingcart.java

import java.util.ArrayList;

public class ShoppingCart {

//instance variables
private String customerName;
private String currentDate;
private ArrayList<ItemToPurchase> cartItems = new ArrayList<ItemToPurchase>();

//Default constructor
public ShoppingCart() {
customerName = "";
currentDate = "";
}

//parameterized constructor
public ShoppingCart(String customerName, String currentDate) {
this.customerName = customerName;
this.currentDate = currentDate;
}

//getter methods
public String getCustomerName() {
return customerName;
}

public String getCurrentDate() {
return currentDate;
}

//add items
public void addItem(ItemToPurchase item) {
cartItems.add(item);
}

//remove item
public void removeItem(String name) {
for (ItemToPurchase i : cartItems) {
if (i.getName().equalsIgnoreCase(name)) {
cartItems.remove(i);
return;
}
}

System.out.println("Item not found in cart");
}

//modify the item
public void modifyItem(ItemToPurchase item) {
for (int i = 0; i < cartItems.size(); i++) {
if (cartItems.get(i).getName().equalsIgnoreCase(item.getName())) {
if (!item.getDescription().equals("none") && !(item.getPrice() == 0) && !(item.getQuantity() == 0)) {
cartItems.add(i, item);
return;
}
}
}

System.out.println("Item not found in cart. Nothing modified");

}

//get total number of items in the cart
public int getNumItemsIncart() {
int sum = 0;
for (ItemToPurchase i : cartItems) {
sum += i.getQuantity();
}
return sum;
}

//get total cost of items in the cart
public int getCostOfcart() {
int sum = 0;
for (ItemToPurchase i : cartItems) {
sum += i.getPrice();
}
return sum;
}

//printing total of each items
public void printTotal() {
System.out.println(customerName + "'s Shopping Cart - " + currentDate);
if (cartItems.isEmpty()) {
System.out.println("Shopping Cart is Empty");
return;
}

System.out.println("Number of Items: " + cartItems.size());
System.out.println();
for (ItemToPurchase i : cartItems) {
i.printItemPurchase();
}
System.out.println();
System.out.println("Total: $" + getCostOfcart());
}

//printing description of all items
public void printDescription() {
System.out.println(customerName + "'s Shopping Cart - " + currentDate);
System.out.println();
if (cartItems.isEmpty()) {
System.out.println("Shopping Cart is Empty");
return;
}
System.out.println("Item Descriptions: ");
for (ItemToPurchase i : cartItems) {
i.printItemDescription();
}
}
}

shoppingcartmanager.java

import java.util.Scanner;

public class ShoppingCartManager {

// method to add an item in the cart
public static void addCartItem(Scanner scan, ShoppingCart cart) {
String itemName, itemDescription;
int itemPrice, itemQuantity;
System.out.println("ADD ITEM TO CART");
System.out.print("Enter the item name : ");
itemName = scan.nextLine();
System.out.print("Enter the item description : ");
itemDescription = scan.nextLine();
System.out.print("Enter the item price : ");
itemPrice = scan.nextInt();
System.out.print("Enter the item quantity : ");
itemQuantity = scan.nextInt();
scan.nextLine();

cart.addItem(new ItemToPurchase(itemName, itemPrice, itemQuantity, itemDescription));

}

// method to remove an item from the cart
public static void removeCartItem(Scanner scan, ShoppingCart cart) {
String itemName;
System.out.println("REMOVE ITEM FROM CART");
System.out.print("Enter the name of item to remove : ");
itemName = scan.nextLine();

cart.removeItem(itemName);
}

// method to change quantity of the cart
public static void changeItemQuantity(Scanner scan, ShoppingCart cart) {
String itemName;
int itemQuantity;
System.out.println("CHANGE ITEM QUANTITY");
System.out.print("Enter the item name : ");
itemName = scan.nextLine();
System.out.print("Enter the new quantity : ");
itemQuantity = scan.nextInt();
scan.nextLine();
cart.modifyItem(new ItemToPurchase(itemName, 0, itemQuantity, "none"));
}

// method to display menu choices and perform the operations on the cart until
// the user quits
public static void printMenu(ShoppingCart cart) {
String choice;
Scanner scan = new Scanner(System.in);
do {
System.out.println("\nMENU");
System.out.println("a - Add item to cart");
System.out.println("d - Remove item from cart");
System.out.println("c - Change item quantity");
System.out.println("i - Output items' description");
System.out.println("o - Output shopping cart");
System.out.println("q - Quit");
System.out.print("\nChoose an option : ");
choice = scan.nextLine();

if (choice.equalsIgnoreCase("a")) {
addCartItem(scan, cart);
} else if (choice.equalsIgnoreCase("d")) {
removeCartItem(scan, cart);
} else if (choice.equalsIgnoreCase("c")) {
changeItemQuantity(scan, cart);
} else if (choice.equalsIgnoreCase("o")) {
System.out.println("OUTPUT SHOPPING CART");
cart.printTotal();
} else if (choice.equalsIgnoreCase("i")) {
System.out.println("OUTPUT ITEMS' DESCRIPTION");
cart.printDescription();
} else if (!choice.equalsIgnoreCase("q"))
System.out.println("Invalid choice");

} while (!choice.equalsIgnoreCase("q"));

}

public static void main(String args[]) {
Scanner sc = new Scanner(System.in);

// taking user input
System.out.println("Enter Customer's Name:");
String name = sc.nextLine();
System.out.println("Enter Today's Date:");
String date = sc.nextLine();

// printing user input
System.out.println();
System.out.println("Customer Name: " + name);
System.out.println("Today's Date: " + date);

ShoppingCart cart = new ShoppingCart(name, date);// created shopping cart object
printMenu(cart);
}
}

How could I implement the contain and min method for a tree in this code.


import java.util.List;
import edu.princeton.cs.algs4.*;


class ProgrammingAssignment1 {

    //////////////////// EXERCICE 1: TWO THREE TREES

    static public <Key extends Comparable<Key>>
    int size (NakedTree<Key> tree) {
      if (tree == null)
        return 0;
      int val = tree.getNKeys ();
      for (int i = 0; i <= tree.getNKeys (); ++i)
        val += size (tree.getChild (i));
      return val;
    }

    //////// EXERCICE 1.1: contains AND min

    static public <Key extends Comparable<Key>>
    boolean contains (NakedTree<Key> tree, Key key) {

       
    }

Hello, I have a problem with understanding this line.

forEach(value.split("<br>"), line, line.trim()).slice(-3).join("\n")

This line is for the open refine program. Could you tell me what this line is trying to do? I have no idea what this is for...

For your information, this line appeared when professor was talking about 'Fetching and Parsing HTML'..

Thank you for answering my question and have a good day!

p.s. My professor told us to insert that line in the expression box and try to figure out what this expression means... As I'm not majoring in CS, it's too difficult for me to understand..;(

Discuss the open-source tools in general. What are the advantages versus disadvantages? What is the life-long learning lesson you think you are able to acquire with this type of assignment? Discuss ethical and global issues.