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11.5.1 Access Specifiers
The different components in a class can be accessed by different
parts from within class or outside the class. The access specifiers Definition
restrict the scope of the uses of data members and member
methods within the class or outside the class. This means the Access specifiers are used to limit the accessibility
visibility of the data members and member methods can be of a certain part of a class. These are also known
controlled by these access specifiers. Java provides three access as Visibility specifiers.
specifiers which are private, public and protected.
The private Specifier
The data members or member methods that are declared with the private access specifier can be accessed only within
the class. Examples of private data members and member methods are:
private int a, b;
private double c, d;
private void sum()
The public Specifier
The data members or member methods that are declared with the public access specifier can be accessed within the
class and outside the class also. Examples of public data members and member methods are:
public int a,b;
double c,d; // by default, a data member is public
public void sum()
void difference() // by default, a member method is public
The protected Specifier
The data members or member methods that are declared with the protected access specifier can be accessed within
the class and inherited class also. Examples of protected data members and member methods are:
protected int a, b;
protected double c, d;
protected void calculate()
The following table shows the visibility scope of all the access specifiers:
Access Specifiers Same class Inherited class Other class
private Can be accessed Cannot be accessed Cannot be accessed
protected Can be accessed Can be accessed Cannot be accessed
public Can be accessed Can be accessed Can be accessed
11.5.2 Data Members
There are two types of data members used in a class. They are instance variables and class variables.
Instance Variables
Instance variables are also known as non-static data members. These variables are declared within the class but
outside the member methods. They are created whenever any object is generated. The instance variables associated
with different objects contain different values. For example:
class IVariables
{
int a;
double b;
//member methods
}
264264 Touchpad Computer Applications-X

