What is the explicit use of 'this' keyword?

Question

5.00/5 (1 vote)

See more:

class Rectangle:Shape
{
    double height;
    double width;

    public Rectangle(double height,double width)
    {
       this.height=height;
       this.width=width;
    }
}

class Rectangle:Shape
{
    double rec_Height;
    double rec_Width;

    public Rectangle(double height,double width)
    {
        rec_Height=height;
        rec_Width=width;
    }
}

What I have tried:

My question is why do we use the this keyword?

In my code:

1). I have first initialized the class fields with 'this' keyword.
2). I have again initialized without 'this' keyword.

If I can do it both ways then why do I need to use the 'this' keyword? I mean what is the scenario where 'this' keyword must be used?

Please explain as simply possible as I am quite new to these concepts

Posted 13-Jul-23 6:50am

Samriddha Chowdhury

Updated 13-Jul-23 7:44am

Add a Solution

Comments

[no name] 13-Jul-23 13:15pm

"this" is implied in this case. It's use is more obvious if you have "local variables" of the same name; in which case "this" is needed to differentiate the variable from the "class member".

PIEBALDconsult 13-Jul-23 15:17pm

It's optional there, but I always use it anyway.

Ravi Bhavnani 13-Jul-23 19:58pm

Me too. It's now part of my team's coding guidelines.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

FreedMalloc · Answer 1 · 2023-07-13T07:23:00

Solution 1

The keyword 'this' tells the compiler that you are dealing with a class attribute and not some other variable of the same name.

It also tells someone else reading your code that a variable being used is a class attribute and not some other variable defined further up in the method. It can make your code clearer and easier to read and understand to a reviewer, someone trying to use your code, or even future you that has to pick up the code at some later date.

Both your examples above are valid. But the first one allows you to use the more natural terms 'height' and 'width' in both the class and constructor. 'This' just makes it clear which is which.

Posted 13-Jul-23 7:23am

FreedMalloc

Comments

Samriddha Chowdhury 13-Jul-23 13:58pm

@FreedMalloc thank you sir. So it is only explicitly for understanding whether it is a class field right? No technical aspect to understand?

Dave Kreskowiak 13-Jul-23 14:26pm

Documentation exists for reasons like you're experiencing right now.

this keyword - C# Reference | Microsoft Learn[^]

FreedMalloc 13-Jul-23 14:29pm

Yes. But also that the field you are using is the one for the current instance of the class.
Graeme_Grant has listed a very good link in Solution 2. I think it explains things far better than I can and also gives other usages for 'this' in C#.

Graeme_Grant · Answer 2 · 2023-07-13T07:44:00

Solution 2

Here is the link to the official documentation for the above usage: this keyword - C# Reference | Microsoft Learn[^]

Quote:
The this keyword refers to the current instance of the class.

Posted 13-Jul-23 7:44am

Graeme_Grant

Comments

BillWoodruff 20-Jul-23 3:33am

+5 current instance is the key concept, here.