//---------------------------------------------this keyword usage in the program---------------------------------
//program1
package java2;
public class Java2 {
int age;
String name;
Java2()
{
System.out.println("hi");
}
Java2(int age,String name)
{
this.age=age;//to avoid the conflict between the variable names we need to use this keyword.
//if we won't use this keyword the default value for the instance variable will be assigned.
this.name=name;
}
void display()
{
System.out.println(age+" "+name);
}
public static void main(String[] args) {
Java2 j=new Java2();
Java2 j1=new Java2(10,"ravi");
Java2 j2=new Java2(20,"prasad");
j1.display();
j2.display();
}
}
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//-----this keyword is used to call the current class constructor-----------------------
//program2
package java2;
public class Java2
{
int no;
String name,addr;
Java2()
{
System.out.println("Welcome");
}
Java2(int no)
{
this();//while calling the constructor using this keyword,,this must be the first statement..
//if this() is in the second statement or in other higher statement then we get the error
this.no=no;
}
Java2(int no,String name)
{
this(no);
this.name=name;
}
Java2(int no,String name,String addr)
{
this(no,name);
//this();---------call for the constructor must be the first statement...
this.addr=addr;
}
void display()
{
System.out.println(no+" "+name+" "+addr);
}
public static void main(String[] args)
{
Java2 j=new Java2(123,"ravi","harihar");
j.display();
}
}
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
//----------------------------using this in calling the current class method----------------------------------------------
package java2;
public class Java2
{
void dvg()
{
System.out.println("Journy begins from Dvg");
}
void chitradurg()
{
dvg();
System.out.println("had a cup of tea in chitradurga");
}
void tumkur()
{
this.chitradurg();//wee can explicitly mention this keyword as well.
System.out.println("had snaks in tumkur");
}
void bangalore()
{
tumkur();//calling normal method.. //internally this.tumkur() will be called....
this.chitradurg();//this keyword can be used for the second statement as well for calling the normal methods..
//but the constructor call must be done at the first statement only.
System.out.println("successfully reached Bangalore");
}
public static void main(String []args)
{
Java2 j=new Java2();
j.bangalore();
}
}
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//-------------using this keyword as reference to the current class...and printing the address---------------------------
package java2;
public class Java2
{
void sample(Java2 a)
{
System.out.println(a);
}
void sample1()
{
sample(this);//this refers to the current class reference
System.out.println(this);
}
public static void main(String [] args)
{
Java2 j=new Java2();
j.sample1();
System.out.println(j);
}
}
