Lab Session-6 CSIT221 Fall 2002

1
Lab Session-6 CSIT221 Fall 2002

• A Note About Destructors
• Using Pointers
• Implementing Stacks

2
Destructors

• Destructors perform the opposite function of
  constructors
• A destructor is a member functions of a class and
  it has the same name as the class
• Destructor runs automatically when an object
  belonging to its class is destroyed. It ensures
  clean up operations
• See an example source code

3
Example Class Definition

• include ltiostreamgt
• using namespace std
• class menu
• public
• menu()
• bool reserved()
• void viewseats()
• menu()
• private
• char bus 94

4
Example Member Functions

• bool menureserved()
• coutltlt"Reserving....."ltltendl
• return true
• void menuviewseats()
• coutltlt"View seats....."ltltendl

5
Example Constructor and Destructor

• menumenu()
• coutltlt"Constructor runs now"ltltendl
• menumenu()
• coutltlt"Destructor runs now"ltltendl

6
Example Client Code

• void main()
• menu mymenu
• if (mymenu.reserved())
• coutltltRuns OKltltendl
• mymenu.viewseats()

7
Lab Exercise (Demo Not Required)

• Define a pointer variable. Get an array of
  integers from the system using this pointer.
  Initialize the array to all odd integers from 0
  to 20. Write a for loop to sum the contents of
  the array and produce the result. Delete the
  array (Use delete ptr) and print the sum.

8
Lab Exercise (Demo Due Oct 8th Sec 01 and Oct
9th Sec 02)

• (Section 2 will use the assignment submission
  page located at http//www.cs.fredonia.edu/zubair
  i/submit_221.html to submit this lab due to the
  start of Fall Break on Oct 10th).
• Implement a character stack of size 10 using the
  source code in chapter 4 lectures. Push the
  characters FALLltspacegtBREAKS into the stack then
  pop them out and display FALL BREAK on the
  screen. Find the problem in your program and fix
  it so that any illegal push or pop is prevented.