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Thread: the word "this"

  1. #1
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    Default the word "this"

    I see the term, "this" used here and there and I don't understand what it means. I have searched around and has been said it means the current item. Well, I understand current item when using a cursor traversing through a linked list and how it stops at the current item. maybe that's it? Even if I'm hitting the nail on the head here, I don't understand how "this" is used. I have seen "this" used in two ways.

    one way was something like this: this.xyz = xyz;

    another way I am seeing it now in my book in the binary trees chapter is this:
    {
    right = right.removeRightmost( );
    return this;
    }
    Last edited by helloworld922; February 26th, 2010 at 01:07 AM.


  2. #2
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    Default Re: the word "this"

    This refers to the current object you're method is working with. Note that this can only be referenced in a non-static method (otherwise, there is no object you're working with)

    public static void main(String[] args)
    {
         System.out.println(this.toString()); // Syntax error: We're inside a static method right now
    }

    It is often used to clear-up which field/variable you are referring to because by default, local variables will cover up instance variables and static fields.

    public Class A
    {
         int number;
         public A(int number)
         {
              this.number = 5; // The field number
              System.out.println("This number is " + this.number);
              System.out.println("The local number is " + number);
         }
     
     
         public static void main(String[] args)
         {
              new A(3);
         }
    }

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