queue.py

#Menu Driven Program to perform queue operations

Queue=list() # A default queue using list() function.

rear = front = -1      #Initializing the queue position.

#Inserting element into a queue.

def Insert_Queue(Queue,rear):
    
    Ch='Y'
    
    while Ch == 'Y' or Ch == 'y'or Ch == 'Yes':
        
        val=input("Enter the value to be added into the queue: ")

        rear+=1
        
        Queue.append(val) # Adding element into queue list.
        
        
        print ("Do you want to add more...<y/n>: ", end="")
        
        Ch = input()

        if Ch == 'N' or Ch == 'n' or Ch == 'No' or Ch == 'NO':
            
            break
        
    return rear


#Removing queue elements

def Remove_Queue(Queue, rear):

    Qlen = len(Queue)  # Finds total elements in the queue.

    if Qlen <= 0:     # Checks if queue is empty or not.
        
        print("Queue is empty")

    else:

        rear-=1

        val = Queue.pop(0) # Removing from front of the queue.


        print("Value deleted from queue is", val)

    return rear

# Showing Queue elements

def Show_Queue(Queue,rear):

    front = 0

    Qlen = len(Queue)  # Finds total elements in the queue.

    if Qlen <= 0:     # Checks if queue is empty or not.
        
        print("Queue is empty")

    else:

        print("The queue elements are...")

        while (front <= rear):     # Queue elements processed.

            print(Queue[front],end=" ")

            front+=1


while (True):

    front = -1

    print()
    
    print()

    print ('STACK OPERATION')

    print ('-----------------')

    print ('1. Adding elements to a queue')

    print ('2. Removing elements from a queue')

    print ('3. Showing elements of a queue')

    print ('4. Exit from queue operation')

    print()

    Opt= int(input( "Enter your option: "))

    print()

    if (Opt == 1):

        #Insert operation of queue - Adding element at rear of the queue
        
        rear = Insert_Queue(Queue,rear)

    elif (Opt == 2):

        #Delete operation of queue - Deleting element at front of queue
        
        top = Remove_Queue(Queue, rear)

    elif (Opt==3):

        # Traversing / Showing queue element
        
        Show_Queue(Queue,rear)

    elif (Opt==4):
        
        break