#!/usr/bin/env python
# coding: utf-8

# # Implementation of Queue
# 
# In this lecture we will build on our previous understanding of Queues by implementing our own class of Queue!

# ____
# ## Queue Methods and Attributes
# 
# 
# Before we begin implementing our own queue, let's review the attribute and methods it will have:
# 
# * Queue() creates a new queue that is empty. It needs no parameters and returns an empty queue.
# * enqueue(item) adds a new item to the rear of the queue. It needs the item and returns nothing.
# * dequeue() removes the front item from the queue. It needs no parameters and returns the item. The queue is modified.
# * isEmpty() tests to see whether the queue is empty. It needs no parameters and returns a boolean value.
# * size() returns the number of items in the queue. It needs no parameters and returns an integer.

# ____
# ## Queue Implementation

# In[1]:


class Queue:
    def __init__(self):
        self.items = []

    def isEmpty(self):
        return self.items == []

    def enqueue(self, item):
        self.items.insert(0,item)

    def dequeue(self):
        return self.items.pop()

    def size(self):
        return len(self.items)


# In[2]:


q = Queue()


# In[3]:


q.size()


# In[4]:


q.isEmpty()


# In[5]:


q.enqueue(1)


# In[6]:


q.dequeue()


# ## Good Job!