String, a referance type variable? creating confussion

Question

5.00/5 (2 votes)

See more:

MIDL

String ip = new String("str".ToCharArray());
            String p = ip;
            p = "newstr";
            Console.WriteLine(ip);

Output is: str

As it is written in book that

Reference types:
Reference types are allocated on heap and are garbage collected when they are no longer being used. They are created using new operator, and there is no delete operator for these types unlike C++ where user has to explicitly delete the types created using delete operator. In C#, they are automatically collected by garbage collector.
Reference types include:
• Classes
• Interfaces
• Collection types like Arrays
• String

but the op of above program does not satisfy this.

Posted 3-Feb-11 19:35pm

hotthoughtguy

Add a Solution

Comments

Sergey Alexandrovich Kryukov 4-Feb-11 1:41am

Good question...
--SA

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)

Sergey Alexandrovich Kryukov · Answer 1 · 2011-02-03T19:47:00

Great, you know the reference type! Now System.String is what? This is class, right. So... Read you own text. All correct.

This question is interesting. Thank you.

But the string is very special class. It's the reference type, but assignment operator is defined so it logically behaves pretty much like a value type. In fact, this is imitation of value semantic. Same thing with the operator "==". It is not your default comparison of instances of classes. Strings compare "semantically" not referentially. To see the difference, compare strings using object.ReferenceEquals. Objects can be different, referential identity different, but comparison returns true.

There are many good reasons to imitate value semantics in string, as well as making them classes. This has something to do with memory economy and non-mutable nature of strings while keeping intuitive semantic.

The essence of string design can be understood if you learn string interning: http://msdn.microsoft.com/en-us/library/system.string.intern.aspx[^].

—SA

Abhinav S · Answer 2 · 2011-02-03T19:44:00

Solution 1

Strings are also immutable - see here[^] for an explanation.

Posted 3-Feb-11 19:44pm

Abhinav S

Comments

Sergey Alexandrovich Kryukov 4-Feb-11 5:40am

Thank you Abhinav, but I already mentioned that in first place of my answer, last paragraphs.
--SA