This is a Python program to implement a queue.
The program creates a queue and allows the user to perform enqueue and dequeue operations on it.
1. Create a class Queue with instance variable items initialized to an empty list.
2. Define methods enqueue, dequeue and is_empty inside the class Queue.
3. The method enqueue appends data to items.
4. The method dequeue dequeues the first element in items.
5. The method is_empty returns True only if items is empty.
6. Create an instance of Queue and present a menu to the user to perform operations on the queue.
Here is the source code of a Python program to implement a queue. The program output is shown below.
class Queue: def __init__(self): self.items = [] def is_empty(self): return self.items == [] def enqueue(self, data): self.items.append(data) def dequeue(self): return self.items.pop(0) q = Queue() while True: print('enqueue <value>') print('dequeue') print('quit') do = input('What would you like to do? ').split() operation = do[0].strip().lower() if operation == 'enqueue': q.enqueue(int(do[1])) elif operation == 'dequeue': if q.is_empty(): print('Queue is empty.') else: print('Dequeued value: ', q.dequeue()) elif operation == 'quit': break
1. An instance of Queue is created.
2. The user is presented with a menu to perform enqueue and dequeue operations on the queue.
3. The chosen operation is performed by calling the corresponding method of the queue.
Case 1: enqueue <value> dequeue quit What would you like to do? enqueue 3 enqueue <value> dequeue quit What would you like to do? enqueue 1 enqueue <value> dequeue quit What would you like to do? enqueue 0 enqueue <value> dequeue quit What would you like to do? dequeue Dequeued value: 3 enqueue <value> dequeue quit What would you like to do? dequeue Dequeued value: 1 enqueue <value> dequeue quit What would you like to do? dequeue Dequeued value: 0 enqueue <value> dequeue quit What would you like to do? dequeue Queue is empty. enqueue <value> dequeue quit What would you like to do? quit Case 2: enqueue <value> dequeue quit What would you like to do? dequeue Queue is empty. enqueue <value> dequeue quit What would you like to do? enqueue 7 enqueue <value> dequeue quit What would you like to do? dequeue Dequeued value: 7 enqueue <value> dequeue quit What would you like to do? dequeue Queue is empty. enqueue <value> dequeue quit What would you like to do? quit
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