C++ programming language part: 51Destructor

November 11, 2017 bappi ashraf

Destructor

Destructor are functions that are complimentary to constructor. They de-initialize objects when they are destroyed. A destructoris invocked when an object of the class goes out of scope, or when the memory occupied by it is deallocated using the delete operator. It is also the same name that of the class but is prefixed with a ~(tilde) sign.

Program 40_3

//class & object.demo

#include

class nova //class defined

{

private:

int p1,p2,p3; // we can't type p1=5 likk, need a 'constructor'

public:

nova(); //default constructor

nova(int,int); // defined constructor

void data_in(int,int); // member function

void sum();

void data_out();

~nova();

};

nova::nova()

{ cout<<" Look! It's invocked "<

// p1=p2=p3=0;

}

nova::nova(int x,int y) // constructor & class would be the same name

{

cout<<" two constructor are called "<

p1=x;

p2=y;

}

void nova::data_in(int a,int b) //member function

{

p1=a;

p2=b;

}

void nova::sum()

{

p3=p1+p2;

}

void nova::data_out() //scope resolution operator

{

cout<<" The sum is= "<

}

nova::~nova()

{

p1=p2=p3=0;

cout<<" destructor invocked"<

//argument are called so two defferent

// constructor and destructor are called.

}

void main()

{

nova k1,k2(4,3),*k3; // k is called object

k3=new nova(5,10); // new value are assign

k2.sum(); //this is from initialize member data

k3->sum();

k3->data_out();

k2.data_out();

}

Exercise: write a class called word, which will store a string. Include following member function.

@ void store_word(char *cstr) which store the incoming string passed as its parameter.

@ void add_word(char *cstr)., which adds the incoming to the existing content of word

@ void display_word(void), which displays the content of word on standard output[strlen,cat,cpy etc]

@ use default constructor and destructor.

part: 01 Programming Language

part: 02 Compiler

part: 03 Programming Logic

part: 04 Data Type

part: 05 Programming in C++

part: 06 Data Type

part: 07 Get Input from keyboard

part: 08 Operators

part: 09 Arithmetic AssignmentOperators

part: 10 Identifies of Characters

part: 11 do.. while loop

part: 12 unary operators( Incrementand decrement)

part: 13 Decrement

part: 14 for loop

part: 16 Conditional/ternary Operator

part: 17 Break

part: 18 The continue statementforces the next iteration of the loop to take place.

part: 19 Arrays

part: 20 Array Address

part: 21 Arrays and Pointer

part: 22 Two dimensional array

part: 23 Function

part: 24 Function Argument

part: 25 Calling Function

part: 26 Return Values

part: 27 Over Loading Function

part: 29 More about function andothers

part: 30 Passing arrays to function

part: 31 Dynamic memory allocation

part: 32 Library function

part: 33 User define mathematicalfunction (square)

part: 34 I/O Function

part: 35 Boolean Functions

part: 36 Look here's two differentuser define Boolean Functions

part: 37 Function Scope

part: 38 String

part: 39 String I/O

part: 40 Some dafault member function

part: 41 Standard String-Handlingfunction

part: 42 String Array

part: 43 User defined data type

part: 45 Data Storage Type

part: 46 Sratic storage type

part: 47 Extern storage type

part: 48 Classes and Objects

part: 49 Scope Resolution Operator

part: 50 Constructor

part: 51 Destructor

part: 52 Inheritance

part: 53 Overriding Base ClassMembers

part: 54 Scope Resolution with OverriddenMembers

part: 55 Base Class Initialization

part: 56 Multiple Inheritance

part: 57 Protected base ClassInheritance

part- 58 Ambiguity of MultipleClasses

part- 59 Virtual Base Class

part- 60 More about Constructor andDestructor

part- 61 Virtual Function andpolymorphism

part- 62 Virtual function withdynamic polymorphism

part- 63 Streams

part- 64 File Input and Output withabstract data types

part- 65 Writing and Readingcharacter using binary functions

part- 66 The get() function

part- 67 String Input

part- 68 Integer Input and Output

part- 69 File Pointers

part- 70 More abuot Integer Input and Output

part- 71 Exercise:

part- 72 Operator overloading

part- 73 Look here is a program witha class and overload the ==,>,< and += operators

part- 74 Linked List

part- 75 Representing a Node

part- 76 Inserting and Traversing a Node

part- 77 Deleting a Node

part- 78 More about Linked List

part- 79 Programming Logic andTechnique

part- 81 Programming Logic and Technique:

part- 82 Programming Logic andTechnique:

part- 83 Programming Logic andTechnique:

part- 84 Programming Logic andTechnique:

part- 85 Programming Logic and Technique:

Part- 86 assign the content of twostring