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Encapsulation in C++

whereisstuffFebruary 25, 2021 No comments

Encapsulation:

Data encapsulation is used to hide the implementation details from users.
If a data member is private it means it can only be accessed within the same class.
No outside class can access private data member (variable) of other class.

Syntax:

class class_name
{
private data_members;
public: methods()
{
}
};

Example program:

#include<iostream.h>
#include<conio.h>
class Account {
    private:
     int account_number;
     int account_balance;
    public:
     void show_Data() {
          account_number=13456;
          account_balance=5000;
          cout<<"\nBefore deposit of account XXXXX"<<account_number<<" number of balance :"<<account_balance;
    }
     void deposit(int a) {
          if (a < 0) {
              cout<<"\nGiven amount is wrong...";
          }
          else{
                 account_balance = account_balance + a;
                 cout<<"\n\nAfter deposit of current balance :"<<account_balance;
          }
    }
};
void main()
    {
          clrscr();
          Account ac;
          ac.show_Data();
          ac.deposit(200);
          getch();

    }

Output:

Method overloading and overriding in C++

whereisstuffFebruary 25, 2021 No comments

Overriding:

Method overriding is a mechanism in which a subclass inherits the methods of the superclass and sometimes the subclass modifies the implementation of a method defined in the super class.
That means if subclass (Derived class) has the same method as declared in the parent class (base class).
Method overriding is used for runtime polymorphism.

Rules for Java Method Overriding:

The method must have the same name as in the parent class
The method must have the same parameter as in the parent class.
There must be inherited.
A static method cannot be overridden. It can be proved by runtime polymorphism.

Syntax:

class base_class_name
{
return_type method_name(parameter_list)
{
//Statement
}
}

class derived_class_name
{
base_class_method(parameter_list)
{
//Statement
}
}

Example program:

#include<iostream.h>
#include<conio.h>
class Shape {
public:
double a;
void area() {
cout<<"\n\tCalculating area of Rectangle,Circle,Triangle .........";
}
};

class Rectangle:public Shape {
public:
void area(float l,float w) {
cout<<"\n\nEnter length and width of rectangle : ";
cin>>l>>w;
a=l*w; //area=length*width;
cout<<"\nArea of rectangle : "<<a;
}
};

class Circle:public Shape {
public:
void area(float r) {
cout<<"\n\nEnter radius of circle : ";
cin>>r;
a=3.14*r*r; //area=3.14*radius*radius;
cout<<"\nArea of circle : "<<a;
}
};

void main()
{
clrscr();
Shape s;
s.area();
Rectangle r;
r.area(6,3);
Circle c;
c.area(3.2);
getch();
}

Output:

Method overloading:

Overloading is a mechanism in which we can use many methods having the same function name but can pass the different numbers of parameters or different types of parameters.

Syntax:

class base_class_name
{
return_type method_name(parameter_list)
{
//Statement
}
return_type same_method_name(parameter_list)
{
//Statement
}
}

Example program:

#include<iostream.h>
#include<conio.h>
class Shape {
public:
double a;
    void area() {
          cout<<"\n\tCalculating area of Rectangle,Circle,Triangle .........";
    }
};

class Rectangle: public Shape {
   public:
    void area() {
          float l,w;
          cout<<"\n\nEnter length and width of rectangle : ";
          cin>>l>>w;
          a=l*w; //area=length*width;
          cout<<"\nArea of rectangle : "<<a;
    }
};

class Circle:public Shape {
public:
    void area() {
          float r;
          cout<<"\n\nEnter radius of circle : ";
          cin>>r;
          a=3.14*r*r; //area=3.14*radius*radius;
          cout<<"\nArea of circle : "<<a;
    }
};

void main()
{
          clrscr();
          Shape s;
          s.area();
          Rectangle r;
          r.area();
          Circle c;
          c.area();
          getch();
}

Output:

Polymorphism in C++

whereisstuffFebruary 25, 2021 No comments

Polymorphism:

Poly means many and prism means form so polymorphism means many forms.
It is used to perform a single action in different ways.
For example,
Action is drawn and it performance maybe draw a line or draw a circle.

Types of polymorphism:

1. Runtime polymorphism

2. Compile time polymorphism

Runtime polymorphism:

The runtime polymorphism is also called dynamic polymorphism.
It is the best example is method overloading.

Example program:

#include<iostream.h>
#include<conio.h>
class Shape {
public:
double a;
    void area() {
          cout<<"\n\tCalculating area of Rectangle,Circle,Triangle .........";
    }
};

class Rectangle: public Shape {
   public:
    void area() {
          float l,w;
          cout<<"\n\nEnter length and width of rectangle : ";
          cin>>l>>w;
          a=l*w; //area=length*width;
          cout<<"\nArea of rectangle : "<<a;
    }
};

class Circle:public Shape {
public:
    void area() {
          float r;
          cout<<"\n\nEnter radius of circle : ";
          cin>>r;
          a=3.14*r*r; //area=3.14*radius*radius;
          cout<<"\nArea of circle : "<<a;
    }
};

void main()
{
          clrscr();
          Shape s;
          s.area();
          Rectangle r;
          r.area();
          Circle c;
          c.area();
          getch();

}

Output:

Compile-time polymorphism:

The runtime polymorphism is also called static polymorphism.
It is the best example is method overriding.

Example program:

#include<iostream.h>
#include<conio.h>
class Shape {
public:
double a;
void area() {
cout<<"\n\tCalculating area of Rectangle,Circle,Triangle .........";
}
};

class Rectangle:public Shape {
public:
void area(float l,float w) {
//float l,w;
cout<<"\n\nEnter length and width of rectangle : ";
cin>>l>>w;
a=l*w; //area=length*width;
cout<<"\nArea of rectangle : "<<a;
}
};

class Circle:public Shape {
public:
void area(float r) {
//float r;
cout<<"\n\nEnter radius of circle : ";
cin>>r;
a=3.14*r*r; //area=3.14*radius*radius;
cout<<"\nArea of circle : "<<a;
}
};

void main()
{
clrscr();
Shape s;
s.area();
Rectangle r;
r.area(6,3);
Circle c;
c.area(3.2);
getch();
}

Output:

Note:

If you need to detail learning of method overloading and method overriding concepts then please click the below link to helpful.

https://www.whereisstuff.com/2021/02/method-overloading-and-overriding-in-c.html