Queue

Queue

//  queue.hpp
//  Queue
//
//  Created by Sergiy on 24.02.17.

#ifndef queue_hpp
#define queue_hpp

#include <stdio.h>
#include <iostream>
#include <string>

using namespace std;

struct Node
{
    string label;
    Node* next;
};

class FIFO
{
private:
    Node* head;
    Node* tail;
    
public:
    FIFO( );
    bool isEmpty( );
    void enqueue( Node new_node );
    void dequeue( Node * & getNode );
    void getNode( Node * & getNode );
    void print( );
};

#endif /* queue_hpp */


//---------------


//  queue.cpp
//  Queue
//
//  Created by Sergiy on 24.02.17.

#include "queue.hpp"

FIFO :: FIFO()
{
    head = tail = NULL;
}

bool FIFO :: isEmpty()
{
    if (head == NULL)
    {
        return true;
    }
    else
        return false;
}

void FIFO :: enqueue(Node new_node)
{
    Node* addNode = new Node;
    addNode->label = new_node.label;
    addNode->next = NULL;
    
    if ( isEmpty() )
    {
        head = tail = addNode;
        return;
    }
    
    tail->next = addNode;
    tail = addNode;
    return;
}

void FIFO :: dequeue(Node * & getNode)
{
    if ( isEmpty() )
    {
        cout << "\nThe queue is empty. There are no more elements\n";
        return;
    }
    
    getNode->label = head->label;
    
    Node* aux = head;
    head = head->next;
    aux->next = NULL;
    delete aux;
    return;
}

void FIFO :: getNode(Node * & getNode)
{
    getNode->label = head->label;
    return;
}

void FIFO :: print()
{
    Node* aux = head;
    
    while ( aux != NULL )
    {
        cout << aux->label << endl;
        aux = aux->next;
    }
    return;
}

//---------------

//  main.cpp
//  Queue
//
//  Created by Sergiy on 24.02.17.

#include <iostream>
#include <string>
#include "queue.hpp"

using namespace std;

int main( int argc, const char * argv[] )
{
    FIFO new_tail;
    string label;
    Node new_node;
    Node* getNode = new Node;
    char sel;
    
    while ( true )
    {
        cout << "Choose one of the following opetarions:\n";
        cout << "a - Add an element to your TAIL\n";
        cout << "b - Print your queue\n";
        cout << "c - Read the HEAD element\n";
        cout << "d - Remove the last element\n";
        
        cin >> sel;
        
        switch ( sel )
        {
            case 'a':
                cout << "\nEnter a label: ";
                cin >> label;
                new_node.label = label;
                new_tail.enqueue( new_node );
                cout << endl << endl;
                break;
                
            case 'b':
                cout << "\nThe queue is consists of the following elements:" << endl;
                new_tail.print( );
                cout << endl << endl;
                break;
                
            case 'c':
                cout << "\nThe HEAD element of queue has value \"";
                new_tail.getNode( getNode );
                cout << getNode->label << "\"" << endl << endl;
                break;
                
            case 'd':
                cout << "\nThe element with value \"";
                new_tail.dequeue( getNode );
                cout << getNode->label << "\" was removed from the queue" << endl << endl;
                break;
                
            default:
                break;
        }
    }
   
    return 0;
}