C++ Program demonstrate the Stacks in C++

#include <iostream>
#include <stdlib.h>
#include <cstdlib>
 
using namespace std;

class Stack {
 private:
  static const int max = 10;
  int A[max];
  int top;
 public:
  Stack() {top = -1;}
  bool isEmpty();
     bool isFull();
     int pop();
  void push(int x);
  int display();
};

bool Stack::isEmpty()
{
    if(top == -1)
        return true;
    return false;
}
 
bool Stack::isFull()
{
    if(top == max - 1)
        return true;
    return false;
}

int Stack::pop()
{
    if(isEmpty())
    {
        cout<<"Stack is Empty\n";
        system("read");
    }
    int x = A[top];
    top--;
    return x;
}

void Stack::push(int x){
 if(isFull())
    {
        cout<<"Stack is Full!\n";
        system("read");
    }
    top++;
    A[top] = x;
}

int Stack::display(){
 int i;
 //for (i=0;i<10;i++){
 // cout << A[i] << endl;
 //}
 for(i=top;i>=0;i--){
  //cout << "Stack ["+i+"] = ";
  cout << A[i] << endl;
 }
}

int main() {
 int x=0;
 int choice;
 Stack s;
 
 return 0; 
}

TCP Server with netcat

import sys
import socket 
import getopt
import threading 
import subprocess 

listen   = False
command   = False
upload    = False
execute   = ""
target    = ""
upload_destination = ""
port    = 0

def usage():
 print "BHP Net Tool"
 print 
 print "Usage: bhpnet.py -t target_host -p port"
 print "-l --listen    - listen on [host]:[port] for incoming connections"
 print "-e --execute=file_to_run  - execute the given file upon receiving a connections"
 print "-c --command   - initialize a command shell"
 print "-u --upload=destination  - upon receiving connection upload a file and write to [destination]"
 print 
 print 
 print "Examples: "
 print "bhpnet.py -t 192.168.0.1 -p 5555 -l -c"
 print "bhpnet.py -t 192.168.0.1 -p 5555 -l -u=c:\\target.exe"
 print "bhpnet.py -t 192.169.0.1 -p 5555 -l -e=\"cat /etc/passwd\""
 print "echo 'ABCDEFGHI' | ./bhpnet.py -t 192.168.11.12 -p 135"
 sys.exit();

def client_sender(buffer):

 client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 
 try:
  client.connect((target,port))

  if len(buffer):
   client.send(buffer)
  while True:
   recv_len = 1
   response = ""

   while recv_len: 
    data    = client.recv(4096)
    recv_len   = len(data)
    response  += data 

    if recv_len < 4096:
     break
   print response,

   buffer  = raw_input("")
   buffer += "\n"
   
   client.send(buffer)

 except:
  print "[*] Exception! Exiting."
  
  client.close()

def server_loop():
 global target
 
 if not len(target):
  target = "0.0.0.0"

 server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 server.bind((target,port))
 server.listen(5)

 while True:
  client_socket, addr = server.accept()

  client_thread = threading.Thread(target=client_handler,
  args = (client_socket,))
  client_thread.start()

def run_command(command):
 command = command.rstrip()

 try:
  output = subprocess.check_output(command,stdrr=subprocess.STDOUT, shell=True)
 except:
  output = "Failed to execute command.\r\n"

 return output

def client_handler(client_socket):
 global upload
 global execute
 global command

 if len(upload_destination):
  file_buffer = ""

  while True:
   data = client_socket.recv(1024)

   if not data:
    break
   else:
    file_buffer += data
  
  try:
   file_descriptor = open(upload_destination,"wb")
   file_descriptor.write(file_buffer)
   file_descriptor.close()

   client_socket.send("Successfully saved file to %s\r\n" % upload_destination)
  except:
   client_socket.send("Failed to save file to %s\r\n" % upload_destination)

 if len(execute):
  output = run_command(execute)

  client_socket.send(output)
 
 if command:

  while True:
   client_socket.send("<BHP:#> ")

   cmd_buffer = ""
   while "\n" not in cmd_buffer:
    cmd_buffer += client_socket.recv(1024)

   response = run_command(cmd_buffer)

   client_socket.send(response)

def main():
 global listen
 global port
 global execute 
 global command
 global upload_destination
 global target
 
 if not len(sys.argv[1:]):
  usage()
 try:
  opts, args = getopt.getopt(sys.argv[1:],"hle:t:p:cu:", ["help","listen","execute","target","port","command","upload"])
 except getopt.GetoptError as err:
  print str(err)
  usage()
 
 for o,a in opts:
  if o in ("-h","--help"):
   usage()
  elif o in ("-l","--listen"):
   listen = True
  elif o in ("-e","--execute"):
   execute = a
  elif o in ("-c","--commandshell"):
   command = True
  elif o in ("-u","--upload"):
   upload_destination = a
  elif o in ("-t","--target"):
   target = a
  elif o in ("-p","--port"):
   port = int(a)
  else:
   assert False,"Unhandled Option"
 
 if not listen and len(target) and port > 0:
  buffer = sys.stdin.read()
  client_sender(buffer)

 if listen:
  server_loop()
main()
  

C++ Assignment Questions and Answers

Question [5 Marks]

Consider the following program:

int x,y;
cin >> x >> y;
while(x!=0 && y!=0){
if(x>y){
x = x-y;
}else if(x<y){
y = y-x;
}else y=0;
}
cout << x+y << endl;

What will this program print on the following inputs:

a. 12 5 b. 27 39 c. -2 12 d. 23 0
Question [5 Marks]

Write a function that takes as input a positive integer n and returns the n-th harmonic number. Reminder: the n-th harmonic number is equal to 1+(1/2)+(1/3)+(1/4)+...+(1/n)

Question 3 [10 Marks]

Recall that the % operator calculates the integer remainder of a division (e.g. 8%3 is equal to 2). Consider the following code:

void hail(int n)
{
if(n<=1) return;
2
cout n << “ -> ” ;
if(n%2) hail(3*n+1);
else hail(n/2);
}

What will this function print for n=5? For n=17? For n=6?

Question 4 [10 Marks]

Write a function which will be given as input an array, its size and an integer p. The function will then cyclically shift the array p positions to the right: each element is moved p positions to the right, while the last p elements are moved to the beginning of the array. For example: if we have the array [ 1 2 3 4 5 6], shifting 2 positions to the right should give the array [ 5 6 1 2 3 4 ]. Your function should work correctly for negative values of p.

Question 5 [10 Marks]

Write a function which, given an array of integers, returns the integer that appears most frequently in the array. E.g. for the array [ 1 2 3 2 3 4 2 5 ] your function should return 2.

Question 6 [10 Marks]

Write a function that is given two positive integers r,c and allocates a 2-dimensional array with r rows and c columns. The function then returns a pointer to the allocated array.

Question 7 [10 Marks]

For the following exercises recall the definition of a basic linked list node:

struct Node { int data; struct Node* next; };

Write a function which, given a pointer to the first element of a linked list returns true if all elements of the list are unique. In other words, the function should return false if and only if there exist two nodes in the list with the same data.

Question 8 [10 Marks]

Write a function which will be given a pointer to the first node of a linked list and add to the list, for each element, a copy of it appearing immediately after it. For example: suppose we have a list with the following numbers 1,2,3,4. Calling the function should produce the list 1,1,2,2,3,3,4,4.

Answers

Question 1

a.       Input = 12 5     output = 1

b.      Input = 27 39   output = 3

c.       Input = -2 12    output = Program will loop forever

d.      Input = 23 0     output = 23

Question 2

float n,sum=0;

                cin >> n;

                while(n!=0){

                                sum += (1/n);

                                n-=1;

                }

                cout << sum;

Question 3

input: 5

5->16->8->4->2

input: 17

17->52->26->13->40->20->10->5->16->8->4->2

input: 6

6->3->10->5->16->8->4->2

Question 4

void rotate(int *A, int s, int p){

                int i;

                int temp[s];

                for(i =0; i<s; i++){

                                temp[i] = A[i];

                }

                for(i =0; i<s; i++){

                                A[((i+p)%s)] = temp[i];

                }

}

Question 5

int modefinder(int *A){

                int freq=0;

                int top = 0;

                int i,j,mode;

                for(i=0; i<sizeof(A); i++){

                                for(j=0; j<sizeof(A); j++){

                                                if(A[i]==A[j]){

                                                                freq++;

                                                }

                                }

                                if(freq>top){

                                                mode = A[i];

                                                top = freq;

                                }

                                freq = 0;

                }

                return mode;

}

Question 6

int **make2dary(int r,int c){

                int i;

                int **ary = new int *[r];

                for (i=0; i<r; i++){

                                ary[i] = new int[c];

                }

                return ary;

}

Question 7

bool linklistchk(struct Node *head){

                while(head!=0){

                                struct Node *tmp;

                                for(tmp = head->next; tmp!=0; tmp=tmp->next)

                                                if(tmp->data==head->data)

                                                                return false;

                                                                head = head->next;

                }

                return true;

}

Question 8

void dup_eli(struct Node *head){

                while(head!=0){

                                struct Node *cpy = new Node;

                                cpy->data = head->data;

                                cpy->next = head->next;

                                head->next = cpy;

                                head = cpy->next;

                }

}

Singly linked list in C++

#include <iostream>
using namespace std;

// Node class
class Node {
    int data;
    Node* next;

  public:
    Node() {};
    void SetData(int aData) { data = aData; };
    void SetNext(Node* aNext) { next = aNext; };
    int Data() { return data; };
    Node* Next() { return next; };
};

// List class
class List {
    Node *head;
  public:
    List() { head = NULL; };
    void Print();
    void Append(int data);
    void Delete(int data);
};

/**
 * Print the contents of the list
 */
void List::Print() {

    // Temp pointer
    Node *tmp = head;

    // No nodes
    if ( tmp == NULL ) {
    cout << "EMPTY" << endl;
    return;
    }

    // One node in the list
    if ( tmp->Next() == NULL ) {
    cout << tmp->Data();
    cout << " --> ";
    cout << "NULL" << endl;
    }
    else {
    // Parse and print the list
    do {
        cout << tmp->Data();
        cout << " --> ";
        tmp = tmp->Next();
    }
    while ( tmp != NULL );

    cout << "NULL" << endl;
    }
}

/**
 * Append a node to the linked list
 */
void List::Append(int data) {

    // Create a new node
    Node* newNode = new Node();
    newNode->SetData(data);
    newNode->SetNext(NULL);

    // Create a temp pointer
    Node *tmp = head;

    if ( tmp != NULL ) {
    // Nodes already present in the list
    // Parse to end of list
    while ( tmp->Next() != NULL ) {
        tmp = tmp->Next();
    }

    // Point the last node to the new node
    tmp->SetNext(newNode);
    }
    else {
    // First node in the list
    head = newNode;
    }
}

/**
 * Delete a node from the list
 */
void List::Delete(int data) {

    // Create a temp pointer
    Node *tmp = head;

    // No nodes
    if ( tmp == NULL )
    return;

    // Last node of the list
    if ( tmp->Next() == NULL ) {
    delete tmp;
    head = NULL;
    }
    else {
    // Parse thru the nodes
    Node *prev;
    do {
        if ( tmp->Data() == data ) break;
        prev = tmp;
        tmp = tmp->Next();
    } while ( tmp != NULL );

    // Adjust the pointers
    prev->SetNext(tmp->Next());

    // Delete the current node
    delete tmp;
    }
}

int main()
{
    // New list
    List list;

    // Append nodes to the list
    list.Append(100);
    list.Print();
    list.Append(200);
    list.Print();
    list.Append(300);
    list.Print();
    list.Append(400);
    list.Print();
    list.Append(500);
    list.Print();

    // Delete nodes from the list
    list.Delete(400);
    list.Print();
    list.Delete(300);
    list.Print();
    list.Delete(200);
    list.Print();
    list.Delete(500);
    list.Print();
    list.Delete(100);
    list.Print();
}

output

100 --> NULL
100 --> 200 --> NULL
100 --> 200 --> 300 --> NULL
100 --> 200 --> 300 --> 400 --> NULL
100 --> 200 --> 300 --> 400 --> 500 --> NULL
100 --> 200 --> 300 --> 500 --> NULL
100 --> 200 --> 500 --> NULL
100 --> 500 --> NULL
100 --> NULL
EMPTY

Simple C++ calculator program

Code:

#include <iostream>
#include <stdlib.h>

using namespace std;

int add(int a, int b);
int sub(int a, int b);
int multi(int a, int b);
int divi(int a, int b);
int mod(int a, int b);

int main(){
 int a,b,choose;
 
 system("cls");
 
 cout << "\t\t=================================\n";
 cout << "\t\tWelcome to the simple calculator!\n";
 cout << "\t\t=================================\n\n\n";
 
 cout << "--------------------------------------------------------------\n";
 cout << "-> Enter the first number\t: ";
 cin >> a;
 cout << "--------------------------------------------------------------\n";
 cout << "-> Enter the second number\t: ";
 cin >> b;
 cout << "--------------------------------------------------------------\n";
 
 system("cls");
 
 cout << "--------------------------------------------------------------\n";
 cout << "What do you want to do? \n";
 cout << "--------------------------------------------------------------\n\n";
 cout << "--------------------------------------------------------------";
 cout << "1. Addition\n";
 cout << "2. Subtraction\n";
 cout << "3. Multiplication\n";
 cout << "4. Divition\n";
 cout << "5. Modulo\n";
 cout << "--------------------------------------------------------------\n\n";
 cout << "--------------------------------------------------------------\n";
 cout << "Type the number of your choice: ";
 cin >> choose;
 cout << "--------------------------------------------------------------\n\n";
 
 if (choose == 1){
  cout << "--------------------------------------------------------------\n";
  cout << "The output is: " << add(a,b) << endl;
  cout << "--------------------------------------------------------------\n";
 }
 else if (choose == 2) {
  cout << "--------------------------------------------------------------\n";
  cout << "The output is: " << sub(a,b) << endl;
  cout << "--------------------------------------------------------------\n";
 }
 else if (choose == 3){
  cout << "--------------------------------------------------------------\n";
  cout << "The output is: " << multi(a,b) << endl;
  cout << "--------------------------------------------------------------\n";
 }
 else if (choose == 4) {
  cout << "--------------------------------------------------------------\n";
  cout << "The output is: " << divi(a,b) << endl;
  cout << "--------------------------------------------------------------\n";
 }
 else if (choose == 5) {
  cout << "--------------------------------------------------------------\n";
  cout << "The output is: " << mod(a,b) << endl;
  cout << "--------------------------------------------------------------\n";
 }
 else {
  cout << "--------------------------------------------------------------\n";
  cout << "Your input is incorrect, try again!\n";
  cout << "--------------------------------------------------------------\n";
  system("pause");
  main();
 }
 
 system("Pause");
}

int add (int a, int b){
 return a+b;
}

int sub (int a, int b){
 return a-b;
}

int multi(int a, int b){
 return a*b;
}

int divi(int a, int b){
 return a/b;
}

int mod (int a, int b){
 return a%b;
}