Post Lab 24

Tracing Queues

One thing that seemed to catch many of you off guard on the test was the tracing activities. Several of the tracing activities relied on linked lists, and many of you didn't remember how those functions worked. I'm going to try to fix that by giving you more practice with tracing on a weekly basis as part of our post lab activities. Trace the following blocks of code:

Draw the state of the queue at the end of each of these blocks of code.

1.       my_queue = Queue()
   
         for i in range(5):
             my_queue.enqueue(i)
   
         my_queue.dequeue()
         my_queue.dequeue()
       

2.       my_queue = Queue()
   
         for i in range(5):
             my_queue.enqueue(i)
   
         my_queue.dequeue()
   
         for i in range(5, 10):
             my_queue.enqueue(i)
   
         my_queue.dequeue()
         my_queue.dequeue()
         my_queue.dequeue()
       

3.       my_queue = Queue()
   
         for i in range(10):
             if i % 2 == 0:
                 my_queue.enqueue(i)
             else:
                 my_queue.dequeue()
       

4.       my_queue = Queue()
   
         for i in range(10):
             if i % 2 == 0:
                 my_queue.enqueue(i)
             else:
                 removed_value = my_queue.dequeue()
                 my_queue.enqueue(removed_value)
   
       

5.       my_queue = Queue()
   
         for i in range(10):
             if i % 2 == 0:
                 my_queue.enqueue(i)
             elif i % 3 == 0:
                 my_queue.dequeue()
             else:
                 removed_value = my_queue.dequeue()
                 my_queue.enqueue(removed_value)
       

6.       my_queue = Queue()
   
         for i in range(10):
             my_queue.enqueue(i)
   
         while my_queue.peek() != 5:
             my_queue.enqueue(my_queue.dequeue())
   
       

7.       my_queue = Queue()
   
         for i in range(10):
             my_queue.enqueue(i)
   
         while my_queue.peek() != 5:
             if my_queue.peek() % 2 == 0:
                 my_queue.enqueue(my_queue.dequeue())
             else:
                 my_queue.dequeue()
   
       

8.       my_queue = Queue()
         temp_list = []
         for i in range(10):
             my_queue.enqueue(i)
   
         for j in range(5):
             temp_list.append(my_queue.dequeue())
   
         for item in temp_list:
             my_queue.enqueue(item)
       

Submission

Bring this completed worksheet with you to the beginning of class on Wednesday.

Post labs are to be done individually. Sharing files between students is not allowed. Doing so is an Academic Integrity violation, and will be treated as such.