Modify the DemoSalesperson application so each Salesperson has a successive ID number from 111 through 120 and a sales value that ranges from $25,000 to $70,000, increasing by $5,000 for each successive Salesperson. Save the file as DemoSalesperson2.java.

Answer:

Linked lists and arrays are both linear data structures but while an array is a collection of items that can be accessed randomly, a linked list can be accessed sequentially.

A sparse matrix contains very few non-zero elements. For example;

_                        _

|  0   0   3  0  6    |

|   0   5   0  0  4   |

|   2   0   0  0  0   |

|_ 0   0   0  0  0 _|

In the implementation of a sparse matrix, the following are some of the pros and cons of using a linked list over an array;

PROS

i.  Linked lists are dynamic in nature and are readily flexible - they can expand and contract without having to allocate and/or de-allocated memory compared to an array where an initial size might need to be set and controlled almost manually. This makes it easy to store and remove elements from the sparse matrix.

ii. No memory wastage. Since the size of a linked list can grow or shrink at run time, there's no memory wastage as it adjusts depending on the number of items it wants to store. This is in contrast with arrays where you might have unallocated slots. Also, because the zeros of the sparse matrix need not be stored when using linked lists, memory is greatly conserved.

CONS

i. One of the biggest cons of linked lists is the difficulty in traversing items. With arrays, this is just of an order of 0(1) since the only requirement is the index of the item. With linked lists, traversal is sequential which means slow access time.

ii. Storage is another bottle neck when using linked lists in sparse matrix implementation. Each node item in a linked list contains other information that needs to be stored alongside the value such as the pointer to the next or previous item.

Answer:

I believe it is A

Explanation:

Answer:

The program written in Python is as follows

nums = []

for i in range(0,68):

-->nums.append(i)

print(nums)

Explanation:

Please note that --> is used to denote indentation

The first line creates an empty list

nums = []

This line creates an iteration from 0 to 67, using iterating variable i

for i in range(0,68):

This line saves the current value of variable i into the empty list

nums.append(i)

At this point, the list has been completely filled with 0 to 67

This line prints the list

print(nums)

Answer:

Here is the C++ program for Employee class with fields id,name and sal.

#include <iostream>  // to use input output functions

#include <string>  //to manipulate and use strings

using namespace std;   // to access objects like cin cout

class Employee {  //class Employee

private:  

/* the following data members are declared as private which means they can only be accessed by the functions within Employee class */

  string name;  //name field

  int id; //id field

  double sal;   //salary field

public:    

  Employee();  // constructor that initializes an object when it is created

/* setName, setID and setSalary are the mutators which are the methods used to change data members. This means they set the values of a private fields i.e. name, id and sal */

  void setName(string n)  //mutator for name field

     { name = n; }        

  void setId(int i)  //mutator for id field

     { id = i; }        

  void setSalary(double d)  //mutator for sal field

     { sal = d; }  

/* getName, getID and getSalary are the accessors which are the methods used to read data members. This means they get or access the values of a private fields i.e. name, id and sal */

  string getName()  //accessor for name field

     { return name; }        

  int getId()  //accessor for id field

     { return id; }        

  double getSalary()  //accessor for sal field

     { return sal; }  };  

Employee::Employee() {  //default constructor where the fields are initialized

  name = "";  // name field initialized

  id = 0;  // id field initialized to 0

  sal = 0;   }   // sal field initialized to 0

void display(Employee);  

// prototype of the method display() to display the data of Employee

int main() {  //start of the main() function body

  Employee emp;  //creates an object emp of Employee class

/*set the name field to Abc Xyz which means set the value of Employee class name field to Abc Xyz  through setName() method and object emp */

  emp.setName("Abc Xyz");  

/*set the id field to 1234 which means set the value of Employee class id field to 1234  through setId() method and object emp */

  emp.setId(1234);

/*set the sal field to 1000 which means set the value of Employee class sal field to 1000  through setSalary() method and object emp */

  emp.setSalary(1000);    

  display(emp);  }   //calls display() method to display the Employee data

void display(Employee e) {  // this method displays the data in the Employee //class object passed as a parameter.

/*displays the name of the Employee . This name is read or accessed through accessor method getName() and object e of Employee class */

  cout << "Name: " << e.getName() << endl;  

/*displays the id of the Employee . This id is read or accessed by accessor method getId() and object e */

  cout << "ID: " << e.getId() << endl;

/*displays the salary of the Employee . This sal field is read or accessed by accessor method getSalary() and object e */

  cout << "Salary: " << e.getSalary() << endl;  }

Explanation:

The program is well explained in the comments mentioned with each statement of the program.

The program has a class Employee which has private data members id, name and sal, a simple default constructor Employee(), mutatator methods setName, setId and setSalary to set the fields, acccessor method getName, getId and getSalary to get the fields values.

A function display( ) is used to display the Employee data i.e. name id and salary of Employee.

main() has an object emp of Employee class in order to use data fields and access functions defined in Employee class.

The output of the program is:

Name: Abc Xyz                                                                                                      

ID: 1234                                                                                                                  

Salary: 1000

The program and its output are attached.

Answer:

packet filtering

Explanation:

We can use a packet filtering firewall, for something like this, reasons because when visiting a site these types of firewalls should block all incoming traffic and analyze each packet, before sending it to the user. So if the packet is coming from a malicious origin, we can then drop that packet and be on our day ;D

Answer:

According to the principles of design, Repetition refers to the recurrence of elements of the design

One of the advantages of this is that it affords uniformity. Another is that it keeps the user of such a system familiar or with the interface of the operating system.

One major drawback of this principle especially as used in the question is that it creates a familiar route for hackers.

Another drawback is that creates what is called "repetition blindness". This normally occurs with perceptual identification tasks.

The  phenomenon may be  due to a failure in sensory analysis to process the same shape, figures or objects.

Cheers!

Answer:

(b) is used in Traceroute

(d) is used by Ping

Explanation:

ICMP is the short form of Internet Control Message Protocol. It is a protocol used by networking devices such as routers to perform network diagnostics and management. Since it is a messaging protocol, it is used for sending network error messages and operations information. A typical message could be;

i. Requested service is not available

ii. Host could not be reached

ICMP does not use ports. Rather it uses types and codes. Some of the most common types are echo request and echo reply.

Traceroute - which is a diagnostic tool - uses some messages available in ICMP (such as Time Exceeded) to trace a network route.

Ping - which is an administrative tool for identifying whether a host is reachable or not - also uses ICMP. The ping sends ICMP echo request packets to the host and then waits for an ICMP echo reply from the host.

ICMP is not required to solve NAT traversal problem neither does it have a new version in IPV6.

Answer:

Here is the sentinel-controlled while loop:

#include <iostream> //to use input output functions

using namespace std; // to identify objects like cin cout

int main(){ // start of main() function body

int test_score; // declare an integer variable for test scores

//prompts user to enter test scores and type-99 to stop entering scores

cout << "Enter the test scores (enter -99 to stop): ";

cin >> test_score; // reads test scores from user

while (test_score != -99){ // while loop keeps executing until user enters -99

cin >> test_score; } } // keeps taking and reading test scores from user

Explanation:

while loop in the above chunk of code keeps taking input scores from user until -99 is entered. Sentinel-controlled loops keep repeating until a sentinel value is entered. This sentinel value indicates the end of the data entry such as here the sentinel value is -99 which stops the while loop from iterating and taking the test score input from user.

The complete question is that the code should then report how many scores were  entered and the average of these scores. Do not count the end sentinel -99 as a score.

So the program that takes input scores and computes the number of scores entered and average of these scores is given below.

#include <iostream>  // to use input output functions

using namespace std;  // to identify objects like cin cout

int main(){  //start of main function body

double sum = 0.0;  // declares sum variable to hold the sum of test scores

int test_score,count =0;  

/* declares test_scores variable to hold the test scores entered by user and count variable to count how many test scores input by user */

cout << "Enter the test scores (or -99 to stop: ";

//prompts user to enter test scores and type-99 to stop entering scores

cin >> test_score;  // reads test scores from user

while (test_score != -99){  // while loop keeps executing until user enters -99

count++;  /* increments count variable each time a test cores is input by user to count the number of times user entered test scores */

sum = sum + test_score;  // adds the test scores

cin >> test_score;}  // reads test scores from user

if (count == 0)  // if user enters no test score displays the following message

cout << "No score entered by the user" << endl;

else  //if user enters test scores

//displays the numbers of times test scores are entered by user

cout<<"The number of test scores entered: "<<count;

/* displays average of test scores by dividing the sum of input test scores with the total number of input test scores */

cout << "\n The average of " << count << " test scores: " <<sum / count << endl;}

The program along with its output is attached.