CircularQueue.py

class CircularQueue:
    def __init__(self, capacity):
        self.capacity = capacity
        self.queue = [None] * capacity
        self.front = self.rear = -1

    def is_empty(self):
        return self.front == self.rear == -1

    def is_full(self):
        return (self.rear + 1) % self.capacity == self.front

    def enqueue(self, item):
        if self.is_full():
            print("Queue is full. Cannot enqueue.")
            return
        elif self.is_empty():
            self.front = self.rear = 0
        else:
            self.rear = (self.rear + 1) % self.capacity
        self.queue[self.rear] = item

    def dequeue(self):
        if self.is_empty():
            print("Queue is empty. Cannot dequeue.")
            return None
        elif self.front == self.rear:
            item = self.queue[self.front]
            self.front = self.rear = -1
        else:
            item = self.queue[self.front]
            self.front = (self.front + 1) % self.capacity
        return item

    def peek(self):
        if self.is_empty():
            print("Queue is empty.")
            return None
        return self.queue[self.front]

    def display(self):
        if self.is_empty():
            print("Queue is empty.")
        elif self.front <= self.rear:
            for i in range(self.front, self.rear + 1):
                print(self.queue[i], end=" ")
            print()
        else:
            for i in range(self.front, self.capacity):
                print(self.queue[i], end=" ")
            for i in range(0, self.rear + 1):
                print(self.queue[i], end=" ")
            print()


# Example usage:
cq = CircularQueue(5)
cq.enqueue(1)
cq.enqueue(2)
cq.enqueue(3)
cq.enqueue(4)
cq.enqueue(5)

print("Queue elements:")
cq.display()

print("Dequeue:", cq.dequeue())
print("Dequeue:", cq.dequeue())

cq.enqueue(6)
cq.enqueue(7)

print("Queue elements after enqueue:")
cq.display()