c++ visual studio 2019

Do not use #include

(I need a different method than the one below to implement a circular queue) (was told by my professor that other students had the same method)

• Using composition
• Overriding selected public methods with private methods
• Using private inheritance.

The circular queue should expose only the following methods:

back	Returns the value of the last (most recently added) element at the back of the queue.
empty	Tests if the queue is empty.
front	Returns the value of the element at the front of the queue.
pop	Removes an element from the front of the queue
push	Adds an element to the back of the queue.
size	Returns the number of elements in the queue.
print	Prints all values in the queue, from the front to the back.

List2.cpp

// Include Header files for string , assert and List2.h #include #include #include #include #include #include "List2.h"

using namespace std;

// Node Constructor with string param Node::Node(string s) { // Set the data to string and previous and next to NULL data = s; previous = NULL; next = NULL; }

// Default List constructor to set first & last to NULL List::List() { first = NULL; last = NULL; }

// method to check if list is empty bool List::empty() const { // compare first == NULL , which indicates empty list return first == NULL ; }

// Print method to print the contents of the list void List::print() { cout << " Contents : " ; // Iterate the list using iterator starting from begining Iterator itr = begin(); for(; !itr.equals( this->end()) ; itr.next() ) { cout << itr.get() << " , " ; } // print the last element cout << itr.get() << " "; } // attach the element at the last void List::push_back(string data) { // create a new node with given data Node* new_node = new Node(data); // compare if the last == null in which case empty list if (last == NULL ) { // make first and last point to the new node first = new_node; last = new_node; } else { // list is not empty // link last node and new node point to each other new_node->previous = last ; last->next = new_node; //make last node as new node last = new_node; } // now to make the link circular again , point last node to first and first to the new node last->next = first ; first->previous = last ; }

void List::insert(Iterator iter, string s) { // check if the position is null if (iter.position == NULL ) { // position is null indicates last node // hence insert at the end and exit push_back(s); return ; }

// INsert in between case // create new node with data Node* new_node = new Node(s); // create iterator to store the temp pointers Node* after = iter.position ; Node* before = after->previous; // reset the previous and next pointers apprpriately new_node->previous = before ; new_node->next = after ; // check if before pointer is last , which means we are inserting at the begining if( before == last) { // reset first to the new node first = new_node ; // and firs point to the last node first->previous = last ; last->next = first ; } else { // case where in between node before->next = new_node; } }

Iterator List::erase(Iterator iter) { // if iter is null assert assert(iter.position != NULL ); // store previous and next pointers Node* remove = iter.position ; Node* before = remove->previous; Node* after = remove->next ; // check if node to be removed is first if ( remove == first ) { // if both first and last are equal then make the list empty if ( first == last ) { first = NULL ; last = NULL ; } else { // reset first to after and last pointer on first node. first = after ; first->previous = last; last->next = first ; } } else before->next = after ; // check if node to be removed is last if ( remove == last ) { // if both first and last are not equal reset the last pointer to first if ( first != last ) { last = before ; first->previous = last; last->next = first ; } } else { after->previous = before; } // delete the node and return the iterator delete remove ; Iterator r ; r.position = after ; r.container = this; return r; }

// this method returns the pointer to first position Iterator List::begin() { Iterator iter; iter.position = first ; iter.container = this; return iter; }

// this iterator method returns pointer to the last position Iterator List::end() { Iterator iter ; iter.position = last ; iter.container = this; return iter; }

// this iterator method returns pointer Iterator::Iterator() { position = NULL ; container = NULL; }

// This method returns item at iter current position string Iterator::get() const { assert(position != NULL ); return position->data ; }

// this iterator returns next pointer void Iterator::next() { assert(position != NULL); position = position->next; }

void Iterator::previous() { assert(position != container->first); if ( position == NULL ) position = container->last; else position = position->previous; }

bool Iterator::equals( Iterator b ) const { return position == b.position ; } cqueue.h

#ifndef CQUEUE_H #define CQUEUE_H

#include #include #include #include #include #include "List2.h"

using namespace std;

class cqueue : private List { public : cqueue(); string front(); string back() ; bool empty() const ; void pop() ; void push(string dat); int size() const ; void print() ; private : int sz ;

};

#endif cqueue.cpp

#include #include #include #include #include #include "cqueue.h"

using namespace std; // default constructor cqueue::cqueue() : List() { sz = 0 ; }

// THis method returns the element at the begining string cqueue::front() { Iterator itr = List::begin() ; return itr.get(); }

// this method returns element at the last string cqueue::back() { Iterator itr = List::end() ; return itr.get(); }

// CHeck if list is empty bool cqueue::empty() const { return List::empty(); }

// pop internally calls the erase if size is >0 void cqueue::pop() { if ( sz > 0 ) { Iterator itr = List::begin(); List::erase(itr); sz -= 1; } }

// push internally calls the push_back void cqueue::push(string dat ) { sz += 1; List::push_back(dat); }

int cqueue::size() const { return sz; }

void cqueue::print() { List::print(); cout << " Size : " << size() << " "; } testDriver.cpp

#include #include #include #include #include #include "List2.h" #include "cqueue.h"

using namespace std;

int main() { // Tests for Circulat List List cl ; cout << " Empty - " << cl.empty() << " "; for ( int i = 0 ; i < 6 ; i++ ) { cl.push_back(to_string( i )) ; } cl.print(); Iterator itr = cl.begin() ; itr.next() ; itr.next() ; //cl.insert(itr,"xyz"); //itr.next() ; //itr.next() ;

cl.erase(itr); cl.print(); Iterator itr1 = cl.begin() ; cl.erase(itr1); cl.print();

Iterator itr0 = cl.end() ; cl.erase(itr0); cl.print(); Iterator itr2 = cl.begin() ; itr2.next() ; itr2.next() ; cl.insert(itr2,"xyz"); cl.print(); cout << " Empty - " << cl.empty() << " "; // Test for Circular Queue cqueue cq ; cout << " CQueue Empty ? - " << cq.empty() << " "; for ( int i = 0 ; i < 6 ; i++ ) { cq.push(to_string( i )) ; } cq.print(); cout << " Front : " << cq.front() ; cout << " Back : " << cq.back() ; cout << "Poping .. "; cq.pop(); cq.print(); cout << "Poping .. "; cq.pop(); cq.print(); cout << "Poping .. "; cq.pop(); cq.print(); cout << "Poping .. "; cq.pop(); cq.print(); cout << "Poping .. "; cq.pop(); cq.print(); cout << "Poping .. "; cq.pop(); cq.print(); //for( ; !cq.empty() ; cq.pop()); cq.print(); }