CIRCULAR QUEUE USING TEMPLATES

IMPLEMENTATION OF CIRCULAR QUEUE USING TEMPLATES

The following code gives the idea to implement circular queue using templates.

/**********************************************************************************

Implementation of circular queue ADT using an Array

**********************************************************************************/

#include<iostream.h>

#include<conio.h>

#define MAX 10

// Creating a generic Queue class

template <class Type>

class Queue

{

 Type Que[MAX];

 int front,rear;

 public:

 void init()

 {

front=-1;

        rear=0;

 }

 void insert(Type ch);

 Type delet();

 void display(); 

};

/*

----------------------------------------------------

insert function

----------------------------------------------------

*/

template <class Type>

void Queue<Type>::insert(Type item)

{

 if (front==(rear+1)%MAX)

 {

cout << "Circular Queue is full\n";

return;

 }

 if(front==-1)

 {

front=0;

rear=0;

 }

 else

rear=(rear+1)%MAX;

 Que[rear] = item;//inserting the item in the Que

}

/*

----------------------------------------------------

delet function

----------------------------------------------------

*/

template <class Type>

Type Queue<Type>::delet()

{

 Type val;

 if((front==-1)||(front>rear))

 {

cout << "Circular Queue is empty\n";

return 0; // return null on empty stack

 }

 val= Que[front];//item to be deleted

 if(front==rear)

front=rear=-1;

 else

front=(front+1)%MAX;

 return val;

}

template <class Type>

void Queue<Type>::display()

{

 int i;

 if(front==-1)

cout<<"\n Circular Queue is Empty";

 i=front;

 while(i!=rear)

 {

cout<<"\n   "<<Que[i];

i=(i+1)%MAX;

 }

 cout<<"\n   "<<Que[i];

 cout<<"\n";

}

/*

----------------------------------------------------

The main function

----------------------------------------------------

*/

void main()

{

 Queue <char> Q1;

 Queue <int> Q2;

 int i;

 clrscr();

 Q1.init();

 Q2.init();

 Q1.insert('p');

 Q1.insert('q');

 Q1.insert('r');

 cout<<"\n The Circular Queue of characters is ..."<<endl;

 Q1.display();

 Q2.insert(10);

 Q2.insert(20);

 Q2.insert(30);

 cout<<"\n The Circular Queue of integers is ..."<<endl;

 Q2.display();

 cout << "\n Delete from Queue of characters: "<<endl;

 for (i=0; i<3; i++)

cout<<"  "<<Q1.delet() << "\n";

 cout << "Delete from Queue of integers: "<<endl;

 for (i=0; i<3; i++)

cout<<"  "<<Q2.delet() << "\n";

// demonstrate double queue

 Queue <double> Q3;

 Q3.init();

 Q3.insert(1.1);

 Q3.insert(1.2);

 cout<<"\n The Circular Queue of doubles is ..."<<endl;

 Q3.display();

 cout << "Delete from Queue of doubles: "<<endl;

 for (i=0; i<2; i++)

cout<<"  "<<Q3.delet() << "\n";

 getch();

}