A Simple Queue with templates

Monday, 20 December 2010 03:54


//

// SimpleQueue.cpp 

//

// Demonstrates a Simple Queue with templates 

// Modified 11/15/2010



#include 

#include 



#define TRUE true

#define FALSE false

#define NULL 0





template  class Node

{

public:

  Type type;



  Node(const Type& type,Node* previous,Node* next)

  {

  

    this->type=type;

	this->previous=previous;

	this->next=next;

  }

  Node* previous;

  Node* next;

};



// the class with the template.

template  class Queue

{

public: 

  Queue();

  Type& font();

  const Type &front() const;

  void push(const Type&);// add element to back of Queue

  void pop(); // remove element from head of queue.

  bool empty() const; // true if no elements in the Queue.

private:

  Node * first;

  Node * last;

}; // end class Queue.



// implements the methods in the class Queue

template  

Queue::Queue()

{

  first=NULL;

  last=NULL;

}



template 

const Type& Queue::front() const

{

  // we are not going to check for the 

  // exceptional conditions that can be arise in this code.

  return last->type;

}



template 

void Queue::push(const Type& type)

{

  if(first==NULL)

  {

     // create a new node

    Node * new_node =new Node(type,NULL,NULL);

	first=new_node;

	last=new_node;

	return;

  }else{

    Node* new_node=new Node(type,NULL,first);

	first->previous=new_node;

	first=new_node;

	return;

  }

}



template 

void Queue::pop()

{

  if(last==NULL)

    return ; // DO NOTHING

  else

  {

    Node * tmp_node=last;

	last=last->previous;

	delete tmp_node;

  }

}



template 

bool Queue::empty() const

{

  if(last==NULL)

    return TRUE;

  else

    return FALSE;

}

 

// main method

int main(int argc,char** argv)

{

  Queue integer_queue;

  for(int i=0;i<100;i++)

    integer_queue.push(i);

  

  // now print the array;

  for(int i=0;i<100;i++)

  {

    int front=integer_queue.front();

    std::cout<	integer_queue.pop();

  }

  return 0;

}