Lecture 8

Learning objectives

After this class, you should be able to:

1. Given certain operations on a circular array, draw a figure that shows its state at the end of those operations.
2. Give the time complexity of the different operations on a circular array.
3. Implement features of a circular array.
4. Give applications where a circular array can be useful.
5. Given certain operations on a stack or a queue, draw a figure that shows the state of the data structure at the end of those operations.
6. Give the time complexity of the different operations on a stack or a queue.
7. Implement features of a stack or a queue, using other data structures, such as circular arrays or linked lists.
8. Give applications where stacks or queues can be useful.

Reading assignment

1. Sections 3.6, 3.7.
2. Lecture: Stacks and Queues.

Exercises and review questions

• Exercises and review questions on current lecture's material

  (Note: Use a circular array based implementation unless we mention otherwise.)

  1. Give a sequence of operations such that a circular array looks as shown in the figure below. Also give the array positions corresponding to the beginning and end of the circular array.

     a

     b

  2. Let us assume a circular array has the following data:

     c

     d

     a

     b

     and we now try to push_front an 'e'. Show how the circular array will look like after this insert operation.

  3. Implement the back member function of a circular array.
  4. Implement the front member function of a circular array.
  5. Implement the push_back member function of a circular array.
  6. Implement the pop_back member function of a circular array.
  7. Implement the pop_front member function of a circular array.
  8. Implement the [] operator of a circular array.
  9. If a circular array looked liked in the question 2, and we push_front an e, but want the new circular array to look like:

     e

     a

     b

     c

     d

     then how should the push_front code be changed? Note that this is a different implementation of a circular array.

  10. Give a real-world application for circular arrays. (Post your answer on the discussion board)
  11. Let us perform the following operations on a stack: push(3), push(2), push(1), pop(). Draw a figure to show the state of the stack. If the underlying data structure were a circular array, with initial capacity 2, then show the final state of the circular array too. If the underlying data structure were a doubly-linked list, then show the final state of the list too.
  12. Let us perform the following operations on a queue: push(3), push(2), push(1), pop(). Draw a figure to show the state of the queue. If the underlying data structure were a circular array, with initial capacity 2, then show the final state of the circular array too. If the underlying data structure were a doubly-linked list, then show the final state of the list too.
  13. Will it be efficient to implement a stack using a vector?
  14. Will it be efficient to implement a queue using a vector?
  15. Will it be efficient to implement a stack using a singly linked list?
  16. Will it be efficient to implement a queue using a singly linked list?
  17. Show an implementation of a stack's pop and push functions, where the underlying data structure is a doubly linked list.
  18. Give a real-world application for (i) stacks and (ii) queues. (Post your answer on the discussion board)

• Questions on next lecture's material
  1. None.

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Last modified: 19 Sep 2011