Methods and this keywords

-

 

this  keyword:-
It is  called as an object reference or reference variable because it refers an  object.
It always refers current object .
It is implicitly present in instance method ,constructor and initialization block
It is explicitly required to access an instance variable whenever both instance and local variable names are same
Example 1:-
this keyword is implicitly present

Class Demo 

{

int x=10;                //instance variable

void show()            // instance method

    {

System.out.println(x);

    }

Public static void main(String args[])

{

Demo d=new demo();     // object 

d.show();

}

}


Example 2:-

Class Demo 


int x=10;             // instance variables  

void show()   // instance method 

  {

int x=20; //local  variables  

System.out.println(x);

System.out.println(this.x);

}

 Public static void main(String args[])

{

Demo d1=new demo();

Demo d2=new demo(); // object 

d1.x=d1.x+2;

d2.x=d2.x+2;

d1.show();

d2.show();

}

}



Example 3:-


Class Demo

{

int x=10;

void show()

{

    int x=20;

    System.out .println(x);

    System.out .println(this.x);

}

Public static void main(String args[])

{

Demo d=new Demo();

d.show();

}

}



Methods
  • A group of Statements into a single logical unit is called as method.
  •  Methods are used to perform the tasks.
  • A Method that is defined as a member of a class is known as instance method.
 In java methods are divided into four categories:-
1)Methods with arguments and with return value. 
2)Methods with arguments  and without return value.
3)Methods without arguments  and with return value.
4)Methods without arguments  and without return value.
1)Methods with arguments and with return value:-

Class Demo 

{

int max(int a, int b)    // instance method

{

       if (a>b)

       return  a;

               else

                     return  b;


}

  Public static void main(String args[])

{

  Demo d=new Demo(); //object

                    int x=d.max(45,89);

                    System.out.println(x);

}

}


**Names of area in method

 

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