Page 122 - DCAP404 _Object Oriented Programming

Kumar Vishal, Lovely Professional University Unit 6: Constructors and Destructors

Unit 6: Constructors and Destructors Notes

CONTENTS
Objectives
Introduction
6.1 Need for Constructor and Destructor
6.1.1 Constructor

6.1.2 Destructor
6.2 Copy Constructor
6.3 Dynamic Constructors
6.4 Parameterized Constructors
6.5 Constructors with Default Arguments
6.6 Destructors
6.7 Constructor/Destructor with Static Members

6.8 Summary
6.9 Keywords
6.10 Review Questions
6.11 Further Readings

Objectives

After studying this unit, you will be able to:

 Recognize the need for constructor and destructors
 Describe the copy constructor
 Explain the dynamic constructor
 Discuss the destructors

 Explain the constructor and destructors with static members
Introduction

When an object is created all the members of the object are allocated memory spaces. Each object
has its individual copy of member variables. However the data members are not initialized
automatically. If left uninitialized these members contain garbage values. Therefore it is important
that the data members are initialized to meaningful values at the time of object creation.
Conventional methods of initializing data members have lot of limitations. In this unit you will
learn alternative and more elegant ways initializing data members to initial values.

When a C++ program runs it invariably creates certain objects in the memory and when the
program exits the objects must be destroyed so that the memory could be reclaimed for further
use.

C++ provides mechanisms to cater to the above two necessary activities through constructors
and destructors methods.

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