Introduction for Inheritance
OOP में Inheritance ये बहुत ही महत्वपूर्ण हिस्सा है | Inheritance में दो प्रकार के के classes होते है |- Base Class : Base class को 'parent या super class' भी कहा जाता है | Base class में data members और member functions होते है |
- Derived Class : Derived class को 'child या sub class' भी कहा जाता है |
Derived class; Base class की properties को inherit करता है |
Inheritance के पांच प्रकार है |
- Single Inheritance
- Multilevel Inheritance
- Multiple Inheritance
- Hierarchical Inheritance
- Hybrid Inheritance
Syntax for Inheritance
class Derived_Class : Access_Specifier Base_Class
1. Single Inheritance
Single Inheritance ये Inheritance का सबसे पहला और आसान प्रकार है |Single Inheritance में एक Base Class की properties एक derived class को inherit की जाती है |
Syntax for Single Inheritance
class Base_class_Name
{
// body_of_Base_class
};
class Derived_class_Name : Access_Specifier Base_class_Name
{
//body_of_Derived_class
};
जब member functions class के अन्दर declare किये जाते है, तब Syntax
return_type Member_function(){ some_code; }
जब member functions class के बाहर declare किये जाते है, तब Syntax
return type class_name :: member_function(){ some_code; }
निचे दिए हुए program में member functions को class के अन्दर declare किया गया है |
Example for Single Inheritance
Source Code :
#include <iostream.h>
using namespace std;
class Employee{
int emp_id;
char emp_name[20];
int emp_salary;
public:
void getdata(){
cout<<"Enter Employee id : ";
cin>>emp_id;
cout<<"Enter Employee name : ";
cin>>emp_name;
cout<<"Enter Employee salary : ";
cin>>emp_salary;
}
void putdata(){
cout<<"Employee id : "<<emp_id<<endl;
cout<<"Employee name : "<<emp_name<<endl;
cout<<"Employee salary : "<<emp_salary<<endl;
}
};
class fitness : public Employee
{
float height,weight;
public:
void accept(){
cout<<"Enter Height in feet: ";
cin>>height;
cout<<"Enter Weight in kg: ";
cin>>weight;
}
void display(){
cout<<"Employee Height is "<<height<<" feet"<<endl;
cout<<"Employee Weight is "<<weight<<" kg"<<endl;
}
};
int main(){
fitness F;
cout<<" Enter Employee details"<<endl;
F.getdata();
F.accept();
cout<<"Employee details are"<<endl;
F.putdata();
F.display();
return 0;
}
Output:
Enter Employee details Enter Employee id : 5 Enter Employee name : Rakesh Enter Employee salary : 20000 Enter Height in feet: 5.9 Enter Weight in kg: 65 Employee details are Employee id : 5 Employee name : Rakesh Employee salary : 20000 Employee Height is 5.9 feet Employee Weight is 65 kg
2. Multilevel Inheritance
Multilevel Inheritance; Inheritance का दूसरा प्रकार है |Multilevel Inheritance में एक base class और दो derived class होते है |
Multilevel Inheritance में derived class का base class होता है और derived class का भी derived class होता है |
Syntax for Multilevel Inheritance
class Base_class_Name
{
// body_of_Base_class
};
class Derived_class_Name1 : Access_Specifier Base_class_Name
{
//body_of_Derived_class1
};
class Derived_class_Name2 : Access_Specifier Derived_class_Name1
{
//body_of_Derived_class2
};
Source Code:
#include <iostream.h>
using namespace std;
class base_class{
public:
void show(){
cout << "I am a Base Class."<<endl;
}
};
class derived_class1 : public base_class{
public:
void get(){
cout << "I am a Derived Class1."<<endl;
}
};
class derived_class2 : public derived_class1{
public:
void display(){
cout << "I am a Derived Class2."<<endl;
}
};
int main(){
derived_class2 d; // Access all data from derived_class2
d.show();
d.get();
d.display();
return 0;
}
Output:
I am a Base Class. I am a Derived Class1. I am a Derived Class2.
3. Multiple Inheritance
Multiple Inheritance ये Inheritance का तीसरा प्रकार है |Multiple Inheritance में एक से अधिक base classes हो सकते है और एक derived class होता है |
Derived class को दो या दो से ज्यादा base classes को inherit किया जाता है, उसे Multiple Inheritance कहते है |
Syntax for Multiple Inheritance
class Base_class_Name1
{
// body_of_Base_class
};
class Base_class_Name2
{
//body_of_Base_class2
};
class Derived_class_Name : Access_Specifier Base_class_Name1, Access_Specifier Base_cass_Name2,.......
{
//body_of_Derived_class2
};
Source Code :
#include <iostream.h>
using namespace std;
class A{
public:
display1(){
cout<<"Class A"<<endl;
}
};
class B{
public:
display2(){
cout <<"Class B"<<endl;
}
};
class C: public B, public A{
public:
display3(){
cout <<"Class C"<<endl;
}
};
int main(){
C obj;
obj.display1();
obj.display2();
obj.display3();
return 0;
}
Output :
Class A Class B Class C
4. Hierarchical Inheritance
Hierarchical Inheritance ये Inheritance का चौथा प्रकार है |Hierarchical Inheritance में एक base class और एक से अधिक derived classes होते है |
Syntax for Hierarchical Inheritance
class Base_classname
{
//body_of_Base_class
};
class derived_class_Name1 : Access_Specifier Base_class_Name
{
//body_of_derived_class1
};
class derived_class_Name2 : Access_Specifier Base_class_Name
{
//body_of_derived_class2
};
Source Code :
#include <iostream.h>
using namespace std;
class A{
public:
display1(){
cout<<"Class A"<<endl;
}
};
class B : public A{
public:
display2(){
cout <<"Class B"<<endl;
}
};
class C : public A{
public:
display3(){
cout <<"Class C"<<endl;
}
};
int main(){
B b;
C c;
c.display1();
b.display2();
c.display3();
return 0;
}
Output:
Class A Class B Class C
5. Hybrid Inheritance
Hybrid Inheritance ये Inheritance का पांचवा और आखिरी प्रकार है | इसे 'Virtual Inheritance' भी कहा जाता है |Hybrid Inheritance; एक से ज्यादा inheritance का combination है |
Syntax for Hybrid Inheritance(Multilevel, Multiple)
class base_class_Name
{
//body_of_Base_class
};
class derived_class_Name1 : Access_Specifier base_class_Name
{
//body_of_derived_class1
};
class derived_class_Name2
{
//body_of_derived_class2
};
class derived_class_Name3 : class derived_class_Name1, class derived_class_Name2
{
//body_of_derived_class3
};
Source Code :
#include <iostream.h>
using namespace std;
class A{
public:
display1(){
cout<<"Class A"<<endl;
}
};
class B : public A{
public:
display2(){
cout <<"Class B"<<endl;
}
};
class C{
public:
display3(){
cout <<"Class C"<<endl;
}
};
class D : public C, public B{
public:
display4(){
cout <<"Class D"<<endl;
}
};
int main(){
D obj;
obj.display1();
obj.display2();
obj.display3();
obj.display4();
return 0;
}
Output:
Class A Class B Class C Class D
Hybrid Inheritance using Virtual Function
Syntax for Hybrid Inheritance using Virtual Function
class base_class_Name
{
//body_of_Base_class
};
class derived_class_Name1 : virtual Access_Specifier base_class_Name //or Access_Specifier virtual base_class_Name
{
//body_of_derived_class1
};
class derived_class_Name2 : virtual Access_Specifier base_class_Name //or Access_Specifier virtual base_class_Name
{
//body_of_derived_class2
};
class derived_class_Name3 : class derived_class_Name1, class derived_class_Name2
{
//body_of_derived_class3
};
अगर निचे दिए हुए program को देखे तो virtual function दिखेगा |
दिया हुआ program अगर बिना virtual function के compile करे तो 'member ambiguous' का error आ जाता है |
इसका कारण ये है कि, class A; class B और class C इन दोनों पर derived किया गया है और class D पर class B और class C की वजह से class A की दो copies class D पर आयी है | और आखिर में class D का object ही सब inheritance का data access कर रहा है |
Virtual Function लेने का कारण ये है कि, class A की सिर्फ एक copy ही class D को मिल जाए |
Source Code :
#include <iostream.h>
using namespace std;
class A{
public:
display1(){
cout<<"Class A"<<endl;
}
};
class B : virtual public A{ //or public virtual A
public:
display2(){
cout <<"Class B"<<endl;
}
};
class C : virtual public A{ //or public virtual A
public:
display3(){
cout <<"Class C"<<endl;
}
};
class D : public C, public B{
public:
display4(){
cout <<"Class D"<<endl;
}
};
int main(){
D obj;
obj.display1();
obj.display2();
obj.display3();
obj.display4();
return 0;
}
Output:
Class A Class B Class C Class D
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