Inheritance in C++

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In this article, single inheritance has been demonstrated.

Syntax:

class DerivedClassName: AccessSpecifier BaseClassName

{

};

Program Reference: Cpp_Programs/ Day_06/ Inheritance_Public_01.cpp

#include<stdlib.h> 
#include<iostream>

class A
{
  private:
   int a;

  protected:
   int b;

  public:
   int c; 

   void reada(void) 
   {
     std::cout<<"\nInitialize A: \n\tPlease Enter two Values: "; 
     std::cin>>a>>b; 
     c=a*10+b;
     std::cout<<"Returning From Class A....";
   }
 
   void writea(void)
   {
     std::cout<<"\nDisplay A:\n\t A = "<<a<<"\tB= "<<b<<"\tC= "<<c<<"\nReturning From A....";
   }  
};

class B: public A
{
  private:
   int a;

  protected:
   int b;

  public:
   int c;
 
   void readb(void) 
   {
     std::cout<<"\nInitialize B: \n\tPlease Enter two Values: "; 
     std::cin>>a>>b; 
     c=a*10+b; 
     std::cout<<"\nReturning From B";
   }

   void writeb(void)
   {
     std::cout<<"\nDisplay B: \n\tA = "<<a<<"\tB= "<<b<<"\tC= "<<c; std::cout<<"\nReturning From B....\n";
   }
};

int main(void)
{
  B obb;

  system("clear");  //TO CLEAR THE SCREEN [use clrscr(); in windows]

  std::cout<<"\n\t\t\tDemonstration of Inheritance(Public)\n";

  obb.reada();
  obb.writea();
  obb.writeb();

  obb.readb();
  obb.writea();
  obb.writeb();

  std::cout<<"\n\nAssigning A::C=1 From B";
  obb.c=1;
  obb.writea();
  obb.writeb();

  std:: cout<<"\n\nEnd of the Program....\n\n\n";
}
 

Output

 
            Demonstration of Inheritance(Public)

Initialize A: 
    Please Enter two Values: 10 20
Returning From Class A....
Display A:
     A = 10    B= 20    C= 120
Returning From A....
Display B: 
    A = -1217048576    B= 134515211    C= -1218256896
Returning From B....

Initialize B: 
    Please Enter two Values: 11 22

Returning From B
Display A:
     A = 10    B= 20    C= 120
Returning From A....
Display B: 
    A = 11    B= 22    C= 132
Returning From B....


Assigning A::C=1 From B
Display A:
     A = 10    B= 20    C= 120
Returning From A....
Display B: 
    A = 11    B= 22    C= 1
Returning From B....


End of the Program....

Program Reference: Cpp_Programs/ Day_06/ Inheritance_Public_02.cpp

#include<stdlib.h> 
#include <iostream> 

class A
{
  private:
   int a;

  public:
   int b;

   void inita(void) {std::cout<<"\nInitialize A \n"; a=10;b=20; std::cout<<"Returning From A....";}

   void writea(void){std::cout<<"\nDisplay A: \n\tA = "<<a<<"\tB= "<<b; std::cout<<"\nReturning From A....";}  
};

class B: public A
{
  private:
   int x;

  public:
   int y;

   void initb(void) {std::cout<<"\nInitialize B....\n"; x=b; y=30; std::cout<<"Returning From B....";}

   void writeb(void){std::cout<<"\nDisplay B: \n\tX = "<<x<<"\tY= "<<y<<"\tB= "<<b; std::cout<<"\nReturning From B....\n\n";}    
};

int main(void)
{
  B obb;

  system("clear");  //TO CLEAR THE SCREEN [use clrscr(); in windows]

  std::cout<<"\n\t\t\tDemonstration of Inheritance(Public)\n";

  obb.inita();
  obb.writea();
  obb.writeb();

  obb.initb();
  obb.writea();
  obb.writeb();

  std::cout<<"\n\nSet B::Y=1 From B";
  obb.y=1;
  //obb.a=0;
//  obb.x=0;
  obb.writea();
  obb.writeb();

  std::cout<<"\n\nSet A::B=1 From B";
  obb.b=1;
  obb.writea();
  obb.writeb();

  std:: cout<<"\n\nEnd of the Program....\n\n\n";
}

 

Output

            Demonstration of Inheritance(Public)

Initialize A 
Returning From A....
Display A: 
    A = 10    B= 20
Returning From A....
Display B: 
    X = 134515019    Y= -1218433024    B= 20
Returning From B....


Initialize B....
Returning From B....
Display A: 
    A = 10    B= 20
Returning From A....
Display B: 
    X = 20    Y= 30    B= 20
Returning From B....



Set B::Y=1 From B
Display A: 
    A = 10    B= 20
Returning From A....
Display B: 
    X = 20    Y= 1    B= 20
Returning From B....



Set A::B=1 From B
Display A: 
    A = 10    B= 1
Returning From A....
Display B: 
    X = 20    Y= 1    B= 1
Returning From B....



End of the Program....

Program Reference: Cpp_Programs/ Day_06/ Inheritance_Public_03.cpp

#include<stdlib.h> 
#include <iostream>

class A
{
  private:
   int a;

  protected:
   int b;

  public:
   int c;

   void inita(void) {std::cout<<"\nInitialize A "; a=1;b=2;c=3; std::cout<<"\nReturning From A.... ";}

   void writea(void){std::cout<<"\nDisplay Class A: \n\tA = "<<a<<"\tB= "<<b<<"\tC= "<<c; std::cout<<"\nReturning From A.... ";}  
};

class B: public A
{
  private:
   int x;

  protected:
   int y;

  public:
   int z;

   void initb(void) {std::cout<<"\nInitialize B ";x=10;y=20;z=30; c=40; std::cout<<"\nReturning From B.... ";}

   void writeb(void){std::cout<<"\nDisplay Class B: \n\tX = "<<x<<"\tY= "<<y<<"\tZ= "<<z<<"\tC= "<<c; std::cout<<"\nReturning From B.... \n\n";}    
};

int main(void)
{
  B obb;

  system("clear");  //TO CLEAR THE SCREEN [use clrscr(); in windows]

  std::cout<<"\n\t\t\tDemonstration of Public Inheritance\n\t[Private: Not Inheritable\tProtected->Protected\tPublic->Public]\n";

  obb.inita();
  obb.writea();
  obb.writeb();

  obb.initb();
  obb.writea();
  obb.writeb();

  std::cout<<"\n\nAssigning A::C=1 From B";
  obb.c=1;
  obb.writea();
  obb.writeb();

  std:: cout<<"\n\nEnd of the Program....\n\n\n";
}
 

Output

            Demonstration of Public Inheritance   

[Private: Not Inheritable    Protected->Protected    Public->Public]

Initialize A 
Returning From A.... 
Display Class A: 
    A = 1    B= 2    C= 3
Returning From A.... 
Display Class B: 
    X = -1216704512    Y= 134515083    Z= -1217912832    C= 3
Returning From B.... 


Initialize B 
Returning From B.... 
Display Class A: 
    A = 1    B= 2    C= 40
Returning From A.... 
Display Class B: 
    X = 10    Y= 20    Z= 30    C= 40
Returning From B.... 



Assigning A::C=1 From B
Display Class A: 
    A = 1    B= 2    C= 1
Returning From A.... 
Display Class B: 
    X = 10    Y= 20    Z= 30    C= 1
Returning From B.... 



End of the Program....  

Program Reference: Cpp_Programs/ Day_06/ Inheritance_Protected.cpp

#include<stdlib.h> 
#include <iostream> 
using namespace std;

class A
{
  private:
   int a;

  protected:
   int b;

  public:
   int c;

   void inita(void);

   void writea(void){std::cout<<"\n\tDisplay Class A: \n\t\tA= "<<a<<"\tB= "<<b<<"\tC= "<<c<<"\n\tReturning From Class A....\n";}  
};

void A::inita(void) 
{std::cout<<"\n\tInitializing Class A\n\t"; a=1;b=2;c=3;std::cout<<"Returning From Class A...."; }

class B: protected A
{
  private:
   int x;

  protected:
   int y;

  public:
   int z;

   void initb(void) {std::cout<<"\nInitializing Class B";inita();writea(); x=10; y=20; z=30; b=11; c=22; std::cout<<"Returning From Class B....\n\n";}

   void writeb(void){std::cout<<"\nDisplay Class B:";writea(); std::cout<<"\tX = "<<x<<"\tY= "<<y<<"\tZ= "<<z<<"\tC= "<<c;std::cout<<"\nReturning From B....\n\n";}    
};

int main(void)
{
  B obb;

  system("clear");  //TO CLEAR THE SCREEN [use clrscr(); in windows]

  cout<<"\n\t\t\tDemonstration of Protected Inheritance\n\t[Private: Not Inheritable\tProtected->Protected\tPublic->Protected]\n";

  cout<<"\nInitially: ";
  obb.writeb();
  obb.initb();
  obb.writeb();
  
//  obb.c=0;  //NOT ACCESSIBLE

  std:: cout<<"\n\nEnd of the Program....\n\n\n";
}

Output

 

            Demonstration of Protected Inheritance

[Private: Not Inheritable    Protected->Protected    Public->Public]

Initially: 
Display Class B:
    Display Class A: 
        A= -1074907844    B= -1219234643    C= -1217686588
    Returning From Class A....
    X = -1216479232    Y= 134515067    Z= -1217687552    C= -1217686588
Returning From B....


Initializing Class B
    Initializing Class A
    Returning From Class A....
    Display Class A: 
        A= 1    B= 2    C= 3
    Returning From Class A....
Returning From Class B....


Display Class B:
    Display Class A: 
        A= 1    B= 11    C= 22
    Returning From Class A....
    X = 10    Y= 20    Z= 30    C= 22
Returning From B....



End of the Program....

Program Reference: Cpp_Programs/ Day_06/ Inheritance_Private.cpp

#include<stdlib.h> 
#include <iostream> 

class A
{
  private:
   int a;

  protected:
   int b;

  public:
   int c;

   void inita(void) 
   {
      std::cout<<"\n\tInitializing Class A\n\t"; 
      a=1;
      b=2;
      c=3;
      std::cout<<"Returning From Class A...."; 
   }

   void writea(void)
   {
     std::cout<<"\n\tDisplay Class A: \n\t\tA= "<<a<<"\tB= "<<b<<"\tC= "<<c;
     std::cout<<"\n\tReturning From Class A....\n";
   }  
};

class B: private A
{
  private:
   int x;

  protected:
   int y;

  public:
   int z;
   void initb(void) 
   {
      std::cout<<"\nInitializing Class B";
      inita();writea();
      x=10;y=20;z=30;c=40;
      std::cout<<"Returning From Class B....\n\n";
   }

   void writeb(void){std::cout<<"\nDisplay Class B:";writea(); std::cout<<"\tX = "<<x<<"\tY= "<<y<<"\tZ= "<<z<<"\tC= "<<c;std::cout<<"\nReturning From B....\n\n";}    
};

int main(void)
{
  B obb;

  system("clear");  //TO CLEAR THE SCREEN [use clrscr(); in windows]

  std::cout<<"\n\t\t\tDemonstration of Private Inheritance\n\t[Private: Not Inheritable\tProtected->Private\tPublic->Private]\n";

  std::cout<<"\nInitially: ";
  obb.writeb();
  obb.initb();
  obb.writeb();

  std:: cout<<"\n\nEnd of the Program....\n\n\n";
}
 
 

Output

            Demonstration of Private Inheritance

[Private: Not Inheritable    Protected->Protected    Public->Public]

 
Initially: 
Display Class B:
    Display Class A: 
        A= -1074519076    B= -1220090707    C= -1218542652
    Returning From Class A....
    X = -1217335296    Y= 134515067    Z= -1218543616    C= -1218542652
Returning From B....


Initializing Class B
    Initializing Class A
    Returning From Class A....
    Display Class A: 
        A= 1    B= 2    C= 3
    Returning From Class A....
Returning From Class B....


Display Class B:
    Display Class A: 
        A= 1    B= 2    C= 40
    Returning From Class A....
    X = 10    Y= 20    Z= 30    C= 40
Returning From B....



End of the Program....