Access modifiers is necessary in object-oriented programming
for data hiding. Access modifiers specifies who can access data and
who can't access data. In class, we can set accessibility of instance member
and static members by access modifiers.
C++ has three access modifiers:
(1) Public
(2) Private
(3) Protected
Public Access Modifier in C++
Public is
keyword is c++ programming language. The variables and functions declared
under public access modifier is accessible to everyone inside
or outside of that class. Other class members can also access public members of
another class.
Public members can accessed by using
(.) dot operator.
During inheritance, public members of
base class accessible to derived class.
Programming example of public access
modifier:
#include<iostream>
using namespace std;
class Rectangle
{
public:
double l, b;
double area();
void setData(double,
double);
};
void Rectangle:: setData(double L,
double B)
{
l = L;
b = B;
}
double Rectangle:: area()
{
return l*b;
}
int main()
{
Rectangle R1;
R1.setData(10.5, 5.0);
cout<<"Area is
"<<R1.area();
return 0;
}
OUTPUT:
Area is 52.5
Private Access Modifier in C++
Private is keyword is c++ programming language. The
variables and functions declared under private access modifier can
be only accessible inside the class. Other class members can not access private
members of another class.
Objects of class can't access private
members directly. But object can access private members by public functions of
that class.
During inheritance, private members do
not inherits.
Friend functions can access private
members indirectly.
Programming example of private access modifier:
#include<iostream>
using namespace std;
class Rectangle
{
private:
double l, b;
public:
double area();
void setData(double,
double);
};
void Rectangle:: setData(double L,
double B)
{
l = L;
b = B;
}
double Rectangle:: area()
{
return l*b;
}
int main()
{
Rectangle R1;
R1.setData(10.5, 5.0);
cout<<"Area is
"<<R1.area();
return 0;
}
OUTPUT:
Area is 52.5
Protected Access Modifier in C++
Protected is keyword is c++ programming language. The
variables and functions declared under protected access modifier can
be only accessible inside the class. Other class members can not access
protected members of another class.
Objects of class can't access protected
members directly. But object can access protected members by public functions
of that class.
During inheritance, protected member of
base class accessible to derived class.
Friend functions can access protected
members indirectly.
Programming example of protected access modifier:
#include<iostream>
using namespace std;
class Rectangle
{
protected:
double l, b;
public:
double area();
void setData(double,
double);
};
void Rectangle:: setData(double L,
double B)
{
l = L;
b = B;
}
double Rectangle:: area()
{
return l*b;
}
int main()
{
Rectangle R1;
R1.setData(10.5, 5.0);
cout<<"Area is
"<<R1.area();
return 0;
}
OUTPUT:
Area is 52.5
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