circularQ2.cpp

#include<conio.h>
#include<process.h>
#include<iostream>
#define MAX 50
using namespace std;
//A class is created for the circular queue
class circular_queue
{
int cqueue_arr[MAX];
int front,rear;
public:
//a constructor is created to initialize the variables
circular_queue(){
  front=rear=-1;	
}

//public function declarations
void insert();
void del();
void display();
};
//Function to insert an element to the circular queue
void circular_queue::insert()
{
int added_item;
//Checking for overflow condition
if ((front == 0 && rear == MAX-1) || (front == rear +1))
{
 cout<<"Overflow";
//return;
}
if (front==-1) /*If queue is empty */
{
front = 0;
rear = 0;
}
else
if (rear == MAX-1)/*rear is at last position of queue */
rear = 0;
else
rear = rear + 1;
cout<<"\nInput the element for insertion in queue:";
cin>>added_item;
cqueue_arr[rear] = added_item;
}/*End of insert()*/
//This function will delete an element from the queue
void circular_queue::del()
{
//Checking for queue underflow
if (front==-1)
{
cout<<"\nQueue Underflow\n";
return;
}
cout<<"\nElement deleted from queue is:"<<cqueue_arr[front]<<endl;
if (front == rear) /* queue has only one element */
{
front=rear=-1;
}
else
if(front == MAX-1)
front = 0;
else
front = front + 1;
}/*End of del()*/
//Function to display the elements in the queue
void circular_queue::display(){
	int front_pos = front,rear_pos = rear;
	if(front_pos==-1)
	cout<<"\n\tQueue is Empty.";
	else{
		for(int i=front_pos;i<=rear_pos;i++){
			cout<<cqueue_arr[i]<<"  : \t";
		}
	}
}
/*void circular_queue::display()
{
int front_pos = front,rear_pos = rear;
//Checking whether the circular queue is empty or not
if (front==-1)
{
cout<<"\nQueue is empty\n";
return;
}
//Displaying the queue elements
cout<<"\nQueue elements:\n";
if(front_pos <= rear_pos )
while(front_pos <= rear_pos)
{
cout<<cqueue_arr[front_pos]<<", ";
front_pos++;
}
else
{
while(front_pos <= MAX-1)
{
cout<<cqueue_arr[front_pos]<<", ";
front_pos++;
}
front_pos = 0;
while(front_pos <= rear_pos)
{
cout<<cqueue_arr[front_pos]<<", ";
front_pos++;
}
}/*End of else*/
//cout<<"\n";
//}/*End of display() */
int main()
{
int choice;
//Creating the objects for the class
circular_queue co;
while(1)
{
//clrscr();
//Menu options
cout <<"\n1.Insert\n";
cout <<"2.Delete\n";
cout <<"3.Display\n";
cout <<"4.Quit\n";
cout <<"\nEnter your choice: ";
cin>>choice;
switch(choice)
{
case 1:
co.insert();
break;
case 2 :
co.del();
getch();
break;
case 3:
co.display();
getch();
break;
case 4:
exit(1);
default:
cout<<"\nWrong choice\n";
getch();
}/*End of switch*/
}/*End of while*/
return 0;
}/*End of main()*/