Circular Queue in C++ not in C A circular queue (https://en.wikipedia.org/wiki/C
ID: 3738556 • Letter: C
Question
Circular Queue in C++ not in C
A circular queue (https://en.wikipedia.org/wiki/Circular_buffer) is one way to implement a queue in the computer. In this assignment, you will implement a CircularQueue class that stores chars, with the following characteristics:
A circular queue is stored in an array.
In addition to the array, the data structure keeps track two indices in the array: a "start" position, and an "end" position.
When an item is enqueued (added) to the queue, it is added at the end position. The end position is then incremented, wrapping around to zero it reaches the end of the array.
To dequeue (remove and return) an item from the queue, we return the item at the start position, and increment the start position (once again wrapping around when it reaches the end of the array).
If start and end are the same, then the queue is empty.
If (end+1) % arrayLength == start, then the queue is full. To add another element to the queue, a new array must be allocated with twice the size of the current one, and all of the elements copied to it, starting at position 0. In C++, after the copying, the old array should be deleted to avoid a memory leak.
Write a class called CircularQueue, or something similar, that implements a circular queue for chars as described above, using an array of chars as the array storage. The queue should start out with an array of length 2.
Write a program that uses your CircularQueue class to answer queries that either add letters to the queue, or remove them from the queue. When a letter is removed from the queue, print out both the letter's position in the array, and the letter itself.
Sample program run
Explanation / Answer
I've taken the array size as '3' and Queue name as "Queue
Program:
#include <iostream>
#define SIZE 3
using namespace std;
class Queue {
private:
char items[SIZE];
int front, rear;
public:
Queue(){
front = -1;
rear = -1;
}
bool isFull(){
if(front == 0 && rear == SIZE - 1){
return true;
}
if(front == rear + 1) {
return true;
}
return false;
}
bool isEmpty(){
if(front == -1) return true;
else return false;
}
void enQueue(char element){
if(isFull()){
cout << "Queue is full";
} else {
if(front == -1) front = 0;
rear = (rear + 1) % SIZE;
items[rear] = element;
cout << endl << "Inserted " << element << endl;
}
}
char deQueue(){
char element;
if(isEmpty()){
cout << "Queue is empty" << endl;
return(-1);
} else {
element = items[front];
if(front == rear){
front = -1;
rear = -1;
} /* Q has only one element, so we reset the queue after deleting it. */
else {
front=(front+1) % SIZE;
}
cout << endl << "Deleted: " << element << " Posotion:" << front;
return(element);
}
}
};
int main()
{
Queue q;
int i;
char c;
do
{
cout<<" Enter your choice: 1.Add 2.Delete 3.Quit ";
cin>>i;
if(i==1)
{
cout<<"Enter Element: ";
cin>>c;
q.enQueue(c);
}
else if(i==2)
q.deQueue();
else
break;
} while(i!=3);
return 0;
}
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