Difference between revisions of "Advanced-C++/C2/More-On-Inheritance/English"

• Multiple Inheritance.
• Hierarchical Inheritance.
• We will do this with the help of examples.

• Ubuntu OS version 11.10 and
• g++ compiler v. 4.6.1

Point the cursor

multiple.cpp

Now, we will see an example on multiple inheritance.

I have already typed the code on the editor.

I will open it.

Note that our filename is multiple.cpp

Let me explain the code.

#include<iostream>

class student

This is the base class.

int roll_no;

char name[20];

These are declared as protected.

class exam_inherit

This is also a base class.

Hence we have two base class here- student and exam_inherit.

In this we have 3 variables- sub1, sub2, sub3 as protected.

This is because protected variables can be accessed by derived class.

class grade:public student, public exam_inherit

{

This inherits the base classes - class "student" and class "exam_inherit".

private:

int avg;

public:

void input();

void display();

void average();

int total;

void input_exam();

void display_exam();

input()

display()

average()

input_exam()

and display_exam()

as public functions.

In this we have "total" as integer variable declared as public.

void grade::input()

{

cout<<"Enter Roll no:";

cin>>roll_no;

cout<<"Enter Name:";

cin>>name;

}

void grade::display()

{

cout<<"Roll no is:"<<roll_no<<"\n";

cout<<"Name is:"<<name <<"\n";

}

void grade::input_exam()

{

cout<<"Enter marks of subject1:";

cin>>sub1;

cout<<"Enter marks of subject2:";

cin>>sub2;

cout<<"Enter marks of subject3:";

cin>>sub3;

}

In this we accept the marks of three subjects as sub1, sub2 and sub3.

void exam::display_exam()

{

total=sub1+sub2+sub3;

cout<<"Total is :" <<total<<"\n";

}

And print the total.

void grade::average()

{

avg=total/3;

cout<<"Average is :"<<avg<<"\n";

}

int main()

exam ex;

gd.input();

gd.input_exam();

gd.display();

gd.display_exam();

gd.average();

}

return 0;

g++ multiple.cpp -o mult

To execute

Type

./mult

g++ space multiple.cpp space -o space mult Press Enter

Type

./mult Press Enter

3

Pratham

67

78

84

I will enter as 3

Enter Name:

I will enter as Pratham

Enter marks of subject1

I will enter as 67

subject2 as 78

subject3 as 84

Output

Roll no is: 3

Name is: Pratham

Total is: 229

Average is: 76

This was multiple inheritance.

Now we will see hierarchical inheritance.

In hierarchical inheritance multiple derived classes inherits from one base class.

I will explain the code now.

protected:

int roll_no;

char name[20];

int sub1;

int sub2;

int sub3;

int total;

In this, we have roll_no as integer variable.

Sub1, sub2, sub3 and total as integer variables.

Then name as character variable.

These are declared protected.

class show:public student

{

This is the derived class.

It inherits the properties of class student.

public:

void input();

void display();

};

These are declared as public functions.

void show::input()

{

cout<<"Enter Roll no:";

cin>>roll_no;

cout<<"Enter Name:";

cin>>name;

}

void show::display()

{

cout<<"Roll no is:"<<roll_no<<"\n";

cout<<"Name is:"<<name <<"\n";

}

class exam:public student

{

This also inherits class student.

We can see that there are two derived class- class exam and class show.

Both the classes inherits the class "student".

public:

void input_exam();

void total_marks();

};

void exam::input_exam()

{

cout<<"Enter marks of subject1:";

cin>>sub1;

cout<<"Enter marks of subject2:";

cin>>sub2;

cout<<"Enter marks of subject3:";

cin>>sub3;

}

It accepts the marks of three subjects- sub1, sub2 and sub3

void exam::total_marks()

{

total=sub1+sub2+sub3;

cout<<"Total is :" <<total<<"\n";

}

It calculates the total of three subjects and print the total.

int main()

{

student st;

show sw;

exam em;

In this we create objects of three classes

as st, sw and ex.

sw.input();

em.input_exam();

sw.display();

em.total_marks();

sw.input();

em.input_exam();

sw.display();

em.total_marks();

return 0;

}

Come back to the terminal. Let me clear the prompt.

g++ hierarchical.cpp -o hier

Type

./hier

Type:

g++ space hierarchical.cpp space-o space hier

Press Enter

Type

./hier

Press Enter

Type:

4

Ashwini

87

67

97

Enter Roll no.:

I will enter as 4

Enter Name:

I will enter as Ashwini

Enter marks of subject1

I will enter as 87

subject2 as 67 and subject3 as 97

Roll no is: 4

Name is: Ashwini

Total is: 251

Come back to our slides.

Summary

In this tutorial, we learnt,

• Multiple Inheritance.

• Hierarchical Inheritance.

Assignment

Create a class area and perimeter.

Find the area and perimeter of a rectangle.

About the Spoken Tutorial Project

It summarizes the Spoken Tutorial project

If you do not have good bandwidth, you can download and watch it

Spoken Tutorial Workshops

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test

For more details, please write to,

contact@spoken-tutorial.org

Acknowledgement

It is supported by the National Mission on Education through ICT, MHRD, Government of Indiaabout:startpage

More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro

Thank You for joining.